Dual-mode LED dimming control system and device

Abstract

The invention discloses a dual-mode LED dimming control system and device, and the system comprises a power module, a control module, a dimming module, a D / A conversion module, a drive module, and an LED light source module, and the power module is used for converting a first input voltage of an input system into a second input voltage; the second input voltage is used for supplying power to the control module and the D / A conversion module; the control module is used for sending a control instruction and controlling the dimming module; the dimming module is used for receiving an instruction of the control module and driving and controlling the manual adjustment module and the remote adjustment module; the driving module is used for receiving the voltage of the D / A conversion module and adjusting the output voltage as a driving signal of the LED light source; the LED light source module is used for selecting lamp beads with corresponding wavelengths and illumination intensities and a connection mode of the lamp beads according to use conditions and scenes, and through design and control of the control module, the driving module and the dimming module, an LED dimming scheme which is free of stroboflash, high in precision and compatible with multiple scenes is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of lighting control, and in particular to a dual-mode LED dimming control system and device. Background Art

[0002] LED light sources have many advantages such as energy saving and environmental protection, long life, high luminous efficiency, rich colors, safety and reliability, fast response and intelligent control.

[0003] LED dimming technology significantly improves the energy efficiency, flexibility, and stability of lighting systems by precisely controlling light output, meeting the needs of diverse scenarios from homes to industrial applications. LED dimming technologies include constant voltage drive, constant current drive, adjustable current drive, pulse width modulation, and brightness balancing. LED dimming methods can be categorized by technology and protocol, including intelligent programmable, MCU-controlled intelligent dimming, mechanical dimming, non-MCU-controlled thyristor dimming, and manual switch dimming. LED dimming requires a multi-control method and multi-technology hybrid dimming mechanism to ensure flicker-free performance and maintain color stability, while also enabling intelligent programmable control and ensuring reliability.

[0004] Traditional dimming technologies and methods have the following technical problems: (1) Flicker problem: low-frequency PWM dimming (<200Hz) can easily cause visual fatigue; analog dimming affects light quality due to color temperature offset; (2) Single control method: most systems only support local or remote single control mode, lacking flexibility; (3) Insufficient energy efficiency and stability: the driver chip efficiency is low under high-voltage input (such as 24V), and the heat dissipation design is complex; (4) Poor communication reliability: remote dimming protocol compatibility is insufficient, and multiple nodes are prone to conflict. Summary of the Invention

[0005] The embodiments of the present application solve the technical problems of the single LED dimming method and poor communication performance in the prior art by providing a dual-mode LED dimming control system and device. The present application proposes a multi-interface, multi-mode collaborative control dimming system through the high-performance processing of the XL4013 chip and the intelligent control capabilities of the STM32. This system can meet the dimming requirements of multiple scenarios and realize a flicker-free, high-precision, and multi-scenario compatible LED dimming solution.

[0006] The embodiment of the present application provides a dual-mode LED dimming control system, including a power module, a control module, a dimming module, a D / A conversion module, a driver module, and an LED light source module, wherein the power module is used to convert a first input voltage of an input system into a second input voltage; the second input voltage is used to power the control module and the D / A conversion module; The dimming module is used to receive dimming instructions, including a manual adjustment module and a remote adjustment module; The control module is used to receive the dimming signal from the dimming module and convert the received dimming signal into a brightness signal; The D / A conversion module is used to receive the brightness value signal of the control module and convert it into a corresponding voltage signal; The driving module is used to receive the voltage signal from the D / A conversion module and adjust the output voltage as a driving signal for the LED light source; The LED light source module is used to select lamp beads and their connection methods corresponding to the wavelength and light intensity according to the usage and scene.

[0007] Preferably, the manual adjustment module is used to adjust the local dimming signal through a knob; the remote adjustment module is used to adjust the remote dimming signal through an RS485 communication interface.

[0008] Preferably, the switching mode of the manual adjustment module and the remote adjustment module is: When the manual adjustment module and the remote adjustment module are running synchronously, if there is a local dimming signal, the local dimming signal is output; if a remote dimming signal is received from the RS485 communication interface, the remote dimming signal is output; When the remote adjustment module is running, the local dimming signal of the manual adjustment module is scanned periodically. If the local dimming signal does not change, the remote adjustment module continues to run; if the local dimming signal changes, the manual adjustment module is immediately switched to run.

[0009] Preferably, the second input voltage is DC5V and DC3.3V, the DC5V is used to power the control module, and the DC3.3V is used to power the D / A conversion module.

[0010] Preferably, the brightness signal output by the dimming module is transmitted to the D / A conversion module through an IIC communication interface.

[0011] Preferably, the LED brightness adjustment chip in the driving module adopts XL4013, the FB pin of the XL4013 is connected to the DAC output of the STM32 in the control module, and the EN pin is connected to the PWM signal.

[0012] Preferably, the SW pin of the XL4013 is externally connected to a Schottky diode and a low ESR capacitor.

[0013] Preferably, the driving module combines analog dimming of XL4013 with high-frequency PWM modulation, adopts voltage fine-tuning in the low brightness range of 0-30%, and enables PWM in the range of 30-100%.

[0014] Preferably, in the LED light source module, 3V lamp beads are selected for the LED lamps, 8 LED lamp beads are connected in series and in parallel in pairs, and 24V dimming is supported.

[0015] The present application also proposes a dual-mode LED dimming control device, including the above-mentioned dual-mode LED dimming control system.

[0016] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. By superimposing the constant current characteristics of the XL4013 with the 200kHz high-frequency PWM signal generated by the STM32, the technical problems of low-frequency PWM dimming (<200Hz) in existing technologies, which easily cause visual fatigue, and analog dimming, which affects light quality due to color temperature shift, are solved. No visible flicker is achieved in the brightness range of 0-100%.

[0017] 2. By switching and configuring the manual and remote adjustment modules, the system solves the existing technical problems of single dimming system control mode and unstable control system. It enables free switching between local and remote control modes, suitable for multiple scenarios. Manual and remote dimming serve as backup for each other, and the system MTBF (mean time between failures) exceeds 100,000 hours. The remote adjustment module also uses RS485 dimming and a customized Modbus-RTU protocol, enhancing the compatibility and stability of remote dimming.

[0018] 3. The present invention integrates the wide voltage input characteristics of the XL4013 chip, the intelligent control capabilities of the STM32, and the dual-mode dimming interface to achieve a flicker-free, high-precision, multi-scenario compatible LED dimming solution. It supports 24V DC power supply and Modbus industrial standards, and can be connected to upper systems such as SCADA and PLC. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the dual-mode LED dimming control system in this application; Figure 2 This is the control flow chart of the dual-mode LED dimming control system in this application; Figure 3 This is the circuit diagram for converting DC24V to DC5V in this application; Figure 4 This is the circuit diagram for converting DC5V to DC3.3V in this application; Figure 5 This is the schematic diagram of the control module in this application; Figure 6 This is a diagram of the potentiometer for the manual adjustment module in this application; Figure 7 This is the RS485 interface circuit diagram of the remote adjustment module in this application; Figure 8This is the D / A conversion module circuit in this application; Figure 9 This is the circuit diagram of the driving module in this application; Figure 10 This is the circuit diagram of the LED light source module in this application. DETAILED DESCRIPTION

[0020] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0021] The present application provides a dual-mode LED dimming control system, including a power module, a control module, a dimming module, a D / A conversion module, a driving module, and an LED light source module.

[0022] like Figure 1 As shown in the figure, the power supply voltage is 24V DC, which is converted to 5V and 3.3V via LDO transformers to power the main control chip and the DA converter chip. The STM32 control module adjusts the D / A conversion voltage based on the adjustment knob or RS485 commands. The voltage of the D / A converter module is a weak current signal and cannot directly drive the load. The driver module XL4013 outputs the LED driving voltage based on the D / A conversion voltage value, thereby achieving the brightness adjustment of the LED light.

[0023] like Figure 2 As shown, the control module sends a control instruction to the dimming module. The dimming module receives the control instruction and adjusts the voltage converted by D / A through the manual dimming module and the remote dimming module, converts it into a brightness value, and completes the dimming.

[0024] When the system is operating, it switches between local and remote modes simultaneously. The main control chip collects the AD data of the local knob, and the brightness is the local value. If there is any local operation, the local command is executed according to the local brightness value. If the RS485 communication interface data is received at this time, it will immediately switch to remote dimming mode. When executing remote control mode, the local knob voltage is regularly scanned. If there is no change, the remote command is continuously executed to enter remote dimming mode. If the local value changes, it will immediately switch to local dimming mode. Whether in local dimming mode or remote mode, the main control chip promptly converts the brightness value into the corresponding voltage value through the IIC communication control conversion chip, thereby adjusting the brightness to the corresponding value.

[0025] 1. Power module The power supply voltage is DC24V, which is converted to 5V and 3.3V through the anti-reverse connection circuit composed of Q1, R20, R21, and D5 and the LM2596S and AMS1117 transformers.

[0026] Q1, R20, R21, and D5 reverse connection protection circuit principle: A PMOS-based DC power supply reverse connection protection circuit utilizes the conduction characteristics of the MOS transistor and the physical properties of the parasitic diode to achieve polarity protection. Its core principle is that when the power supply is connected in the forward direction, the PMOS transistor's gate (G) is grounded through a current-limiting resistor, and the source (S) is connected to the positive input terminal through the body diode. At this time, the body diode is forward-biased and conducts, allowing current to flow through the body diode to the load. Simultaneously, a negative voltage differential (VGS < 0) forms between the source (S) and gate (G), triggering the PMOS transistor to fully conduct. Once turned on, the body diode is short-circuited, and current flows through the PMOS channel instead. At this point, the on-resistance is only in the milliohm range, and the voltage drop is almost negligible.

[0027] When the power supply is reversed, the input voltage polarity reverses, causing the PMOS transistor's gate (G) potential to become higher than its source (S). VGS becomes positive, and the PMOS transistor turns off because it fails to meet the conduction conditions. Simultaneously, the body diode cannot conduct due to reverse bias, completely disconnecting the circuit and blocking reverse current, protecting downstream circuits from damage caused by reverse voltage or short-circuit current. Furthermore, the Zener diode connected in parallel with the gate and source in this circuit limits the VGS voltage, preventing gate breakdown caused by excessive input voltage.

[0028] This circuit not only provides efficient reverse polarity protection but also reduces system power consumption through low on-resistance, making it suitable for high-current scenarios (such as automotive equipment or industrial power supplies). Compared to a diode solution, it avoids the 0.6-0.8V voltage drop loss. Compared to an NMOS solution, the PMOS is directly connected in series with the positive power supply, eliminating the need for an additional boost circuit to achieve gate drive, simplifying the design complexity. However, it should be noted that if the input voltage drops, the PMOS may remain in the on state, causing reverse current, requiring the use of external voltage divider resistors or capacitors to optimize the stability of the gate drive signal.

[0029] LM2596S and AMS1117 voltage conversion principle: LM2596S supports 4.5V-40V input voltage and adopts fixed frequency pulse width modulation (PWM) technology. It converts the input voltage into a pulse signal through the rapid on and off of the internal switch tube (MOSFET). During the on phase, the input voltage stores energy through the inductor; during the off phase, the inductor releases energy to the load and output capacitor, and finally outputs a stable DC voltage through filtering. Figure 3 As shown, LM2596S-5.0 is used to convert DC24V to DC5V. Figure 4 As shown, AMS1117-3.3 converts DC5V to DC3.3V.

[0030] 2. Control module like Figure 5As shown in the figure, the main processing chip uses the STM32G030C8T6 microcontroller, which integrates PWM generator, ADC, USART and other peripherals to achieve: (1) Dynamically switch dimming mode (manual priority / remote lock); Manual priority: The manual knob and RS485 command priority are configurable, and "forced local" mode is supported for scenarios such as emergency lighting.

[0031] (2) Brightness gradient algorithm (S-shaped curve transition to avoid sudden glare); (3) Overvoltage / overcurrent / short circuit protection (save current status to EEPROM after triggering).

[0032] 3. Dimming module Manual dimming module, the manual dimming module is adjusted by manual adjustment knob. When the potentiometer adjusts the circuit, the AD2 voltage is adjusted by the knob. The STM32 determines the adjustment brightness based on the collected voltage value. The AD2 voltage value algorithm is as follows: ; According to the resistance value, V AD2 The maximum value is 2V and the minimum value is 0V. AD2 =2V when the light is brightest, V AD2 =0V, the light is dimmed to the lowest setting. Figure 6 shown.

[0033] The manual dimming module uses a high-precision 20KΩ potentiometer. The STM32 collects the voltage signal through the ADC channel and maps it to a brightness level of 0-4095. The manual dimming module also features a built-in anti-shake algorithm to eliminate contact noise interference from the mechanical knob.

[0034] Remote dimming module, remote dimming module communicates with the outside world through RS485, through the RS485 interface, RS485 conversion chip uses SN65HVD178. It can realize remote brightness adjustment, RS485 interface circuit as follows Figure 7 shown.

[0035] The RS485 module uses an isolated design (such as ADM2483) to prevent ground loop interference.

[0036] The remote dimming module uses a custom Modbus-RTU protocol, supporting both broadcast and individual lamp addressing (with configurable addresses). Messages contain fields such as brightness value, status query, and fault code. The communication baud rate is adaptive (1200-115200 bps), and CRC checksums ensure data integrity.

[0037] The manual dial and RS485 command priorities are configurable, supporting "forced local" mode (e.g., for emergency lighting). During remote dimming, the dial position automatically synchronizes with the current brightness value, preventing sudden brightness changes when switching modes. RS485 nodes support dynamic address assignment, allowing the host computer to scan for online devices via broadcast commands and build a device topology map. If communication is interrupted, the STM32 automatically switches to local dimming mode and attempts to reconnect (with a configurable retry strategy).

[0038] During manual dimming, turning the knob changes the potentiometer's resistance. According to Ohm's law, the voltage changes. The main control chip acquires analog-to-digital data using DMA, converting the analog value into a digital value. Based on the digital value, the main control chip calculates and outputs the corresponding brightness value. During remote dimming, the main control chip receives data from the host computer via the RS485 communication interface. This signal is received via an interrupt and converted into a brightness value according to the message protocol to adjust the brightness. The brightness signal is transmitted to the high-precision DA converter chip via the IIC communication interface. This voltage is then sent to the LED driver chip XL4013, which then drives the LED lights to adjust the brightness.

[0039] The switching process is as follows: After the system starts, the main control chip collects the AD data of the local knob. The brightness is the local value. If there is any local operation, the local command is executed according to the local brightness value. If the RS485 communication interface data is received at this time, it will immediately switch to remote dimming mode. When executing remote control mode, the local knob voltage is regularly scanned. If there is no change, the remote command is continuously executed in remote dimming mode. If the local value changes, it will immediately switch to local dimming mode.

[0040] 4. D / A conversion module The D / A conversion in this application is completed using the MCP4728 chip, which is a four-channel 12-bit digital-to-analog converter (DAC) that supports simultaneous control of four independent analog voltage output channels. It has 12-bit resolution: provides 4096 levels of voltage output, and the differential nonlinearity (DNL) is typically ±0.2 LSB, ensuring high linearity and signal stability. Low output noise: The typical noise level is ±0.2LSB, which is suitable for precision instrument and sensor calibration. The built-in non-volatile memory (EEPROM) supports permanent storage of DAC code, configuration parameters and I²C address in the EEPROM through the I²C interface. The settings can still be retained after power failure, and the output state is automatically restored when power is powered on. This application uses two of the interfaces as adjustment output signals.

[0041] Device configuration process: Device address setting: The default I²C address of the MCP4728 is 0x60 (7-bit address). If there are multiple devices in the system, the address bits need to be modified through the EEPROM to avoid conflicts.

[0042] DAC parameter configuration: Reference voltage mode: Select internal reference (2.048V) and set the gain (1x or 2x). For example, when the gain is 2x, the output range is 0-4.096V.

[0043] EEPROM save (optional): Write the current configuration (such as DAC value, gain, address) to EEPROM to ensure automatic recovery after power failure.

[0044] Voltage output control process: Single-channel voltage output Data frame construction: Send a fast write command (starting with 0x40) and specify the target channel (0-3).

[0045] Convert the target voltage to a 12-bit DAC value (Formula: ). The D / A conversion chip circuit diagram is as follows Figure 8 shown.

[0046] 5. Driver module like Figure 9 As shown, the LED brightness adjustment chip uses XL4013, which adopts the XL4013 step-down DC-DC controller. It supports a wide input voltage of 8-40V (adapting to 24V industrial power supply), the output current can be adjusted in the range of 0-5A, and the conversion efficiency is over 95%.

[0047] By combining the XL4013's constant current characteristics with the 200kHz high-frequency PWM signal generated by the STM32, the XL4013 achieves flicker-free operation within the 0-100% brightness range. Combining the XL4013's analog dimming with high-frequency PWM modulation, voltage fine-tuning is used in the low-brightness range of 0-30%, while PWM is enabled in the 30-100% range, achieving both flicker-free operation and high linearity (non-linear error <1%).

[0048] The STM32 collects the LED load voltage in real time and adjusts the XL4013 feedback terminal resistance through the PID algorithm to offset the current fluctuation caused by temperature drift.

[0049] The output voltage is regulated using voltage signals from the STM32 main control chip and the DAC converter chip. J1 is connected to the positive terminal of the LED, and J2 to the negative terminal. 2.2uF and 0.1uF capacitors are used to eliminate signal jitter and ensure flicker-free LED illumination. The XL4013, the core of a buck DC-DC converter, essentially regulates voltage based on the synergy of closed-loop feedback control and pulse-width modulation (PWM). According to search results, its voltage regulation circuit dynamically adjusts the output voltage by balancing the voltage at the FB (feedback) node. Let the output voltage be VOUT, the network ID for the LED driver be LED-DR1, the FB node voltage be VFB, the FB voltage be a constant, and the voltage regulation signal be VA (analog or PWM equivalent).

[0050] The XL4013's SW pin is connected to an external Schottky diode and a low-ESR capacitor to reduce switching losses. The XL4013's FB pin is connected to the STM32's DAC output for voltage dimming, and the EN pin is connected to the PWM signal.

[0051] 6. LED light source module The LED light source is the light emitting part. The LED lamp can be selected from 3.4V, 6.8V or 9V lamp beads. The corresponding wavelength and light intensity are selected according to the usage and scene. The typical circuit is as follows Figure 10 As shown in the figure, this circuit uses 3V LEDs, 8 LEDs connected in series and two in parallel, and supports 24V dimming. Through testing, it can achieve flicker-free linear dimming.

[0052] 7. This application drives LED light emission and control parameters 7.1 Quantum Mechanical Driving of Semiconductor Luminescence 7.1.1 Band Structure and Photon Emission This application mainly drives LED light emission. The selected LEDs have a wide spectrum range, different power and packaging. However, the light emission of LED is essentially the energy released when the carriers (electrons and holes) in the semiconductor encapsulated material recombine. According to the principles of quantum mechanics, the energy gap E of the semiconductor material is g Determines the energy of the photon and satisfies the relationship: ;

[0053] Where λ is the emission wavelength and h is Planck's constant ( ), c is the speed of light (3×10 8 For example, the Eg of a GaN-based blue LED is ≈ 3.4 eV, corresponding to a wavelength of λ ≈ 365 nm (ultraviolet light). However, the blue light range can be tuned to 450-470 nm through band engineering of the InGaN quantum well structure.

[0054] The dimming range of this application can be adjusted from ultraviolet light to infrared light.

[0055] 7.1.2 Carrier Injection and Recombination Dynamics The LED does not work under reverse voltage. Only under forward bias voltage, the depletion region of the PN junction of the LED is compressed, and electrons are injected from the N region to the P region, and holes are injected from the P region to the N region. The carrier concentration gradient drives them to diffuse near the heterojunction, forming a non-equilibrium carrier distribution. The recombination process can be divided into two categories: Radiative recombination: direct recombination of electrons and holes, releasing photons (the dominant mechanism of luminescence).

[0056] Non-radiative recombination: Defect states or phonon scattering release thermal energy (energy loss).

[0057] Radiative recombination rate R rad It is proportional to the product of carrier concentrations n and p: ; Where B is the bimolecular recombination coefficient (typical value ). For highly doped materials, the concentration of majority carriers is much higher than that of minority carriers. rad ∝min(n, p), limited by the minority carrier concentration.

[0058] 7.2 Quantitative Relationship between Luminous Intensity and Current 7.2.1 Coupling of Current Density and Carrier Concentration The forward current density J is composed of drift current and diffusion current and can be approximated as: ;

[0059] Where q is the electron charge, μ n is the mobility, E is the electric field strength, D n is the electron diffusion coefficient, is the electron concentration gradient. In the low current range (I F <10mA), diffusion current dominates, and the carrier concentration gradient and current show a linear relationship; when driven to high current, the space charge effect leads to an enhanced electric field, the drift current ratio increases, and the nonlinear effect is significant.

[0060] 7.2.2 Mathematical Model of Luminous Intensity Luminous intensity L and radiative recombination rate R rad and light extraction efficiency η ext , dV represents the differential voltage, and active layer represents the active layer parameters: ;

[0061] In the low current range ( ), assuming that non-radiative recombination is negligible (η int ≈1), then , experimentally measured , reflecting the non-uniformity of carrier distribution. , the carrier concentration tends to saturation, m≈1, that is, , is the proportionality coefficient (related to the internal quantum efficiency of the material). The driving current range of this application is 6mA-1A.

[0062] 7.2.3 Efficiency degradation at high current density (D roop effect) When the current density exceeds the critical value (such as J>50A / cm 2 ), the luminous efficiency dropped significantly, the main reasons include: Auger recombination: The three-body collision process consumes energy, the rate R Auger =Cn 3 , where C is the Auger coefficient (in GaN ).

[0063] Carrier leakage: Carriers in the quantum well overflow into the barrier region, resulting in increased non-radiative recombination.

[0064] This application makes compensation adjustments for the efficiency attenuation at high current density.

[0065] 7.3 Experimental Verification and Parameter Extraction 7.3.1 Experimental Fitting of Current-Light Intensity Characteristic Curve Nonlinear regression is performed on experimental data of red, green, blue and other wavelength LEDs to extract key parameters: Linear region slope K1: reflects the internal quantum efficiency of the material (such as K1≈0.8cd / A for blue light LED).

[0066] Turning current density J droop :Marks the starting point of efficiency decay (such as J of InGaN LED droop ≈30A / cm 2 ).

[0067] 7.3.2 Time-Resolved Fluorescence Spectroscopy (TRPL) Analysis By measuring the carrier lifetime , which separates the radiative and non-radiative recombination contributions: ; The experimental results show that under high current The significant shortening verifies the dominant role of Auger recombination.

[0068] 7.3.3 Constant Current Drive In order to avoid positive feedback between temperature and current, a closed-loop constant current source can be used. Through negative feedback, the output current stability meets the following requirements: ; in Indicates the current change, Indicates the current flowing.

[0069] Typical solutions include Buck-Boost topology and PID control algorithm.

[0070] The embodiments of this specific embodiment are all preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made according to the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and variations.

Claims

1. A dual-mode LED dimming control system, characterized in that: It includes power module, control module, dimming module, D / A conversion module, drive module and LED light source module, among which, The power supply module is used to convert the first input voltage of the input system into a second input voltage; the second input voltage is used to power the control module and the D / A conversion module; The dimming module is used to receive dimming instructions, including a manual adjustment module and a remote adjustment module; The control module is used to receive the dimming signal from the dimming module and convert the received dimming signal into a brightness signal; The D / A conversion module is used to receive the brightness value signal of the control module and convert it into a corresponding voltage signal; The driving module is used to receive the voltage signal from the D / A conversion module and adjust the output voltage as a driving signal for the LED light source; The LED light source module is used to select lamp beads and their connection methods corresponding to the wavelength and light intensity according to the usage and scene.

2. The dual-mode LED dimming control system according to claim 1, characterized in that: The manual adjustment module is used to adjust the local dimming signal through a knob; the remote adjustment module is used to adjust the remote dimming signal through an RS485 communication interface.

3. The dual-mode LED dimming control system according to claim 2, wherein: The switching mode of the manual adjustment module and the remote adjustment module is as follows: When the manual adjustment module and the remote adjustment module are running synchronously, if there is a local dimming signal, the local dimming signal is output; if a remote dimming signal is received from the RS485 communication interface, the remote dimming signal is output; When the remote adjustment module is running, the local dimming signal of the manual adjustment module is scanned periodically. If the local dimming signal does not change, the remote adjustment module continues to run; if the local dimming signal changes, the manual adjustment module is immediately switched to run.

4. The dual-mode LED dimming control system according to claim 1, wherein: The second input voltage is DC5V and DC3.3V, the DC5V is used to power the control module, and the DC3.3V is used to power the D / A conversion module.

5. The dual-mode LED dimming control system according to claim 1, wherein: The brightness signal output by the dimming module is transmitted to the D / A conversion module through the IIC communication interface.

6. The dual-mode LED dimming control system according to claim 1, wherein: The LED brightness adjustment chip in the driving module adopts XL4013, the FB pin of the XL4013 is connected to the DAC output of the STM32 in the control module, and the EN pin is connected to the PWM signal.

7. The dual-mode LED dimming control system according to claim 6, wherein: The SW pin of the XL4013 is connected to an external Schottky diode and a low ESR capacitor.

8. The dual-mode LED dimming control system according to claim 6, wherein: The driver module combines the analog dimming of XL4013 with high-frequency PWM modulation, adopts voltage fine-tuning in the low brightness range of 0-30%, and enables PWM in the range of 30-100%.

9. The dual-mode LED dimming control system according to claim 1, wherein: In the LED light source module, 3V lamp beads are selected for LED lamps, 8 LED lamp beads are connected in series and in parallel, and support 24V dimming.

10. A dual-mode LED dimming control device, characterized in that: It comprises the dual-mode LED dimming control system as described in any one of claims 1-9.

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