A multi-stage PWM dimming controller

Abstract

A kind of multi-section PWM dimming controller, including single-chip microcomputer, UART interface connected with single-chip microcomputer and multiplex digital signal isolator, the signal output end of the multiplex digital signal isolator is connected multiplex PWM analog voltage converter, the UART interface is connected isolated 485 transceiver, the signal input end of the isolated 485 transceiver is connected RS485 interface, the output end of the multiplex PWM analog voltage converter is connected for driving light emitting diode current expansion amplifying circuit, the PWM dimming controller further includes power module for powering each device.The utility model can quickly process multiple dimming signals and communication data, realize multiple brightness subsection adjustment, meet the different lighting needs of multiple areas, by the combination of RS485 and UART communication interface, so that the controller can be integrated into a variety of lighting control systems, facilitate integration with other equipment, reduce system development cost, improve versatility and expansibility.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and specifically to a multi-segment PWM dimming controller. Background Technology

[0002] In existing lighting dimming control systems, traditional dimming controllers mostly adopt a single output mode, which is insufficient to meet the independent dimming needs of multiple areas in complex scenarios. Even though some multi-channel dimming controllers have been improved, they still have shortcomings in performance, cost, and versatility. For example, weak main control chip processing power leads to slow dimming response and low accuracy; single communication interface limits system scalability; unreasonable design of signal conversion and drive modules makes them unable to adapt to various luminaire loads, and the overall cost of the equipment is high, which is not conducive to large-scale application. Therefore, there is a need to develop a dimming controller with stronger performance, controllable cost, and comprehensive functions. Utility Model Content

[0003] To overcome the shortcomings of existing technologies, this utility model discloses a multi-segment PWM dimming controller.

[0004] The multi-segment PWM dimming controller of this utility model includes a microcontroller, a UART interface connected to the microcontroller, and a multi-channel digital signal isolator. The signal output terminal of the multi-channel digital signal isolator is connected to a multi-channel PWM analog voltage converter. The UART interface is connected to an isolated RS485 transceiver. The signal input terminal of the isolated RS485 transceiver is connected to an RS485 interface. The output terminal of the multi-channel PWM analog voltage converter is connected to a current amplification circuit for driving light-emitting diodes. The PWM dimming controller also includes a power supply module for powering various devices.

[0005] Preferably, the current amplification circuit is a transistor, with the base of the transistor connected to the output terminal of the multi-channel PWM analog voltage converter and the collector connected to the driven light-emitting diode.

[0006] Preferably, the power supply module includes an AC / DC converter, a first DC / DC converter and a second DC / DC converter connected to the DC voltage output terminal of the AC / DC converter. The DC voltage output terminal of the first DC / DC converter supplies power to the isolated 485 transceiver and the multi-channel digital signal isolator. The DC voltage output terminal of the second DC / DC converter supplies power to the third DC / DC converter. The third DC / DC converter supplies power to the microcontroller, the isolated 485 transceiver, the multi-channel digital signal isolator and the multi-channel PWM analog voltage converter.

[0007] Preferably, the microcontroller, isolated 485 transceiver, multi-channel digital signal isolator, and multi-channel PWM analog voltage converter are STM32F405, ISO3082DWR, CA-IS3722HS, and GP8102S, respectively.

[0008] Preferably, the AC / DC converter is an LM50-23B12R2, the first DC / DC converter and the second DC / DC converter are both B1205S-1WR3, and the third DC / DC converter is an LDO with an output voltage of 3.3V.

[0009] Preferably, it also includes a status indicator light connected to the I / O pin of the microcontroller, and a power indicator light connected to the output of the power module.

[0010] This invention can quickly process multiple dimming signals and communication data, enabling multi-segment brightness adjustment to meet the diverse lighting needs of multiple areas and improve lighting quality for complex lighting scenarios. By combining RS485 and UART communication interfaces, the controller can be integrated into various lighting control systems, facilitating integration with other devices, reducing system development costs, and improving versatility and scalability. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a specific embodiment of the multi-segment PWM dimming controller of this utility model; Figure 2 This is a schematic diagram of a specific implementation of signal transmission in the multi-segment PWM dimming controller of this utility model; Figure 3 This is a schematic diagram of a specific embodiment of the power module described in this utility model; The labels in the diagram are as follows: T - Transistor, VD - External power supply, D1 - Light-emitting diode, D2 - Power indicator, D3 - Status indicator. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments: The multi-segment PWM dimming controller of this utility model includes a microcontroller, a UART interface connected to the microcontroller, and a multi-channel digital signal isolator. The signal output terminal of the multi-channel digital signal isolator is connected to a multi-channel PWM analog voltage converter. The UART interface is connected to an isolated RS485 transceiver. The signal input terminal of the isolated RS485 transceiver is connected to an RS485 interface. The output terminal of the multi-channel PWM analog voltage converter is connected to a current amplification circuit for driving light-emitting diodes. The PWM dimming controller also includes a power supply module for powering various devices.

[0013] This invention allows external signals conforming to the standard Modbus protocol to be input via an RS485 interface. Users can send dimming control commands based on the Modbus protocol via a host computer or other communication devices. These commands are then transmitted to a microcontroller via a UART interface through an isolated RS485 transceiver. The microcontroller, using its built-in software, parses the commands according to the standard Modbus protocol and configures an internal timer based on the input signal requirements to generate a PWM signal with a corresponding duty cycle. This signal is then output to a multi-channel digital signal isolator. The PWM signal is converted by the multi-channel digital signal isolator into a suitable high / low level signal that can be used by a multi-channel PWM analog voltage converter. The multi-channel digital signal isolator shields external interference signals and prevents signal back-transmission to the microcontroller. The output signal from the multi-channel digital signal isolator is then used by the multi-channel PWM analog voltage converter to output an analog voltage signal based on the PWM signal's duty cycle. This analog voltage signal is input to a current amplification circuit to drive the LEDs. Each PWM signal's duty cycle is independently generated and adjusted to produce different analog drive voltages, allowing each LED to emit light at different brightness levels, thus achieving brightness adjustment for corresponding areas of the lighting fixture.

[0014] The microcontroller can be the STM32F405 from STMicroelectronics. The STM32F405 is a 32-bit microcontroller based on the ARM Cortex-M4 core, with a clock frequency of 168MHz. It supports single-precision floating-point operations and can quickly process complex dimming algorithms and communication data. The chip has 512KB-1MB Flash and 192KB SRAM built-in, which can store a large amount of program and dimming parameters; it also includes multiple communication interfaces, facilitating the expansion of controller functions.

[0015] By utilizing the internal timer of the STM32F405 main control chip, multiple independently adjustable PWM signals can be generated. Through the configuration of the timer-related registers, the frequency and duty cycle of the PWM signals can be precisely controlled, thereby achieving precise adjustment of different brightness segments of the lamps and meeting the differentiated lighting needs of multiple areas.

[0016] This invention features one RS485 interface and one UART interface. The RS485 interface uses standard differential signal transmission, offering strong anti-interference capabilities and long transmission distances, making it suitable for long-distance, multi-node industrial communication scenarios. It enables stable data interaction between the controller and a host computer or other devices. The UART interface facilitates connection to other modules with serial communication capabilities, enhancing system compatibility and scalability. The two communication interfaces work together to meet communication needs in various scenarios, supporting the standard Modbus protocol for easy integration with other devices conforming to this protocol, reducing system development difficulty and cost.

[0017] The isolated 485 transceiver, multi-channel digital signal isolator, and multi-channel PWM analog voltage converter are ISO3082DWR, CA-IS3722HS, and GP8102S, respectively, all of which are mature, reliable, and low-cost chips. The CA-IS3722HS has high insulation capability, helping to prevent noise and surges from the data bus or other circuits from entering the local ground terminal, thereby interfering with or damaging sensitive circuits. The GP8102S has high-precision conversion performance, ensuring that the converted 0-10V drive signal is stable and accurate, providing a reliable control signal for dimming lighting fixtures.

[0018] like Figure 3 As shown, the current amplification circuit is a transistor T. The base of the transistor is connected to the output terminal of the multi-channel PWM analog voltage converter, and the collector is connected to the driven light-emitting diode D1. Figure 3 As shown, the positive terminal of the LED can be driven by an external power supply VD, or it can be driven by the DC voltage output from the AC / DC converter in this invention. A 2SD882 transistor can be used to amplify the current of the dimming signal. The 2SD882 transistor has a high current amplification factor and good stability, which can effectively improve the driving capability of the output signal, adapt to multiple sets of lamp loads, and ensure that the dimming signal is not distorted and the lamps operate stably when driving multiple lamps.

[0019] like Figure 2 As shown, the power supply module includes an AC / DC converter, a first DC / DC converter and a second DC / DC converter connected to the DC voltage output terminal of the AC / DC converter. The DC voltage output terminal of the first DC / DC converter supplies power to the isolated 485 transceiver and the multi-channel digital signal isolator. The DC voltage output terminal of the second DC / DC converter supplies power to the third DC / DC converter. The third DC / DC converter supplies power to the microcontroller, the isolated 485 transceiver, the multi-channel digital signal isolator and the multi-channel PWM analog voltage converter.

[0020] The microcontroller only requires one power supply, while the isolated 485 transceiver, the multiplex digital signal isolator, and the multiplex PWM analog voltage converter all involve switching between different level signals and require two power supplies with different voltages. For example, the isolated 485 transceiver and the multiplex digital signal isolator require 3.3V and 5V power supplies, while the multiplex PWM analog voltage converter requires 3.3V and 12V power supplies.

[0021] In one specific embodiment, the AC / DC converter is a Mornsun LM50-23B12R2 small power supply, which converts 220V AC mains power into 12V DC power to power subsequent DC converters. The 12V DC power can also be used to power the driven LEDs and multiple PWM analog voltage converters simultaneously. The first DC / DC converter and the second DC / DC converter are both B1205S-1WR3, which convert 12V DC power into 5V DC power. One of them serves as the power supply for the third DC / DC converter, and the other one is used to power the isolated 485 transceiver and multiple digital signal isolators. The third DC / DC converter TPS7A2033PDBVR is a 3.3V LDO that powers the microcontroller and other devices, as well as the isolated 485 transceiver, multiple digital signal isolators, and multiple PWM analog voltage converters.

[0022] like Figure 2 and Figure 3 As shown, one status indicator D3 and one power indicator D2 can be configured to monitor the LED's operating status. The status indicator is connected to the microcontroller's I / O pins and flashes or remains constantly lit according to the control signal from the main control chip, displaying the controller's operating status in real time, allowing users to quickly determine whether the device is working properly. The power indicator D2 is directly connected to the output of the third DC / DC converter in the power module, and lights up when the power module is supplying power normally, indicating to the user that the device is powered on.

[0023] The isolated 485 transceiver, the multi-channel digital signal isolator, and the multi-channel PWM analog voltage converter are STM32F405, ISO3082DWR, CA-IS3722HS, and GP8102S, respectively.

[0024] This invention can quickly process multiple dimming signals and communication data, enabling multi-segment brightness adjustment to meet the diverse lighting needs of multiple areas and improve lighting quality for complex lighting scenarios. By combining RS485 and UART communication interfaces, the controller can be integrated into various lighting control systems, facilitating integration with other devices, reducing system development costs, and improving versatility and scalability.

[0025] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, other embodiments derived without departing from the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-segment PWM dimming controller, characterized in that, The system includes a microcontroller, a UART interface connected to the microcontroller, and a multi-channel digital signal isolator. The signal output of the multi-channel digital signal isolator is connected to a multi-channel PWM analog voltage converter. The UART interface is connected to an isolated RS485 transceiver. The signal input of the isolated RS485 transceiver is connected to an RS485 interface. The output of the multi-channel PWM analog voltage converter is connected to a current amplification circuit for driving LEDs. The PWM dimming controller also includes a power supply module for powering the various devices.

2. The multi-segment PWM dimming controller according to claim 1, characterized in that, The current amplification circuit is a transistor, with the base of the transistor connected to the output terminal of the multi-channel PWM analog voltage converter and the collector connected to the driven light-emitting diode.

3. The multi-segment PWM dimming controller according to claim 1, characterized in that, The power module includes an AC / DC converter, a first DC / DC converter and a second DC / DC converter connected to the DC voltage output terminal of the AC / DC converter. The DC voltage output terminal of the first DC / DC converter supplies power to an isolated 485 transceiver and a multi-channel digital signal isolator. The DC voltage output terminal of the second DC / DC converter supplies power to a third DC / DC converter, which supplies power to a microcontroller, an isolated 485 transceiver, a multi-channel digital signal isolator and a multi-channel PWM analog voltage converter.

4. The multi-segment PWM dimming controller according to claim 1, characterized in that, The microcontroller, isolated 485 transceiver, multi-channel digital signal isolator, and multi-channel PWM analog voltage converter are STM32F405, ISO3082DWR, CA-IS3722HS, and GP8102S, respectively.

5. The multi-segment PWM dimming controller according to claim 3, characterized in that, The AC / DC converter is LM50-23B12R2, the first and second DC / DC converters are both B1205S-1WR3, and the third DC / DC converter is an LDO with an output voltage of 3.3V.

6. The multi-segment PWM dimming controller according to claim 1, characterized in that, It also includes a status indicator light connected to the I / O pins of the microcontroller, and a power indicator light connected to the output of the power module.

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