Differential parallel drive transmission RGBW constant current control circuit

Abstract

The application discloses a differential parallel driving transmission RGBW constant current control circuit, which comprises a voltage stabilizing power supply circuit, a control circuit and a four-way output constant current driving circuit. The four-way output constant current driving circuit all adopts a PT4121 driving chip as a core. The VIN pin of the PT4121 driving chip is connected to the PWM signal output end of an SM16520P decoding chip respectively. The control circuit takes the SM16520P decoding chip as a core and is used for transmitting four-channel LED driving control signals. The voltage stabilizing power supply circuit is used for providing stable voltage input for the SM16520P decoding chip. The LED circuit of the application adopts the SM16520P decoding chip control, the cost of the scheme is easy to control, the produced product is cheap and has good economic benefits. The driving circuit chip is a step-down constant current controller working in a continuous inductance current conduction mode, and the output current precision can reach ±3% through high-precision light regulating resistors.

Description

Technical Field

[0001] This invention relates to the field of intelligent lighting control technology, specifically a functional differential parallel drive transmission RGBW constant current control circuit capable of driving various high-power LED beads to light up in multiple colors. Background Technology

[0002] With changing living concepts and housing needs, today's homebuyers, in addition to considering factors such as location, floor plan, and construction quality, are increasingly focusing on the surrounding landscape of the community, sometimes even making it the primary factor in their home selection. Under this trend, real estate developers are also placing greater emphasis on the construction and investment in landscaping. Developers often have strong subjective intentions regarding their projects, aiming for unique landscaping to become a key selling point. Therefore, when proposing design concepts and themes, it is crucial to prioritize the practicality of the landscape, proposing themes that are more approachable and relatable to consumers.

[0003] Existing single-color lighting can no longer meet consumer demand; instead, people prefer multi-color lighting. RGB lighting is significantly more versatile than white LED lighting in applications such as car lights, traffic signals, and shop windows. When a specific wavelength of light is needed, RGB color mixing can be done at will, which is where white LED lighting is at a disadvantage. Therefore, it naturally has a stronger effect, as LED colored light has a better color rendering index (CRI). In addition, from a control perspective, ordinary high-power RGB LED lights on the market use microcontrollers, which require software writing, have complex control circuits, and have high microcontroller costs. Summary of the Invention

[0004] The purpose of this invention is to provide a differential parallel drive transmission RGBW constant current control circuit to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A differential parallel drive transmission RGBW constant current control circuit includes a voltage regulated power supply circuit, a control circuit, and a four-output constant current drive circuit. The four-output constant current drive circuit includes a red light drive circuit, a green light drive circuit, a blue light drive circuit, and a white light drive circuit. The red light drive circuit, green light drive circuit, blue light drive circuit, and white light drive circuit all use the PT4121 driver chip as the core. The VIN pin of the PT4121 driver chip is connected to the PWM signal output terminal of the SM16520P decoding chip.

[0007] The control circuit is based on the SM16520P decoding chip and is used to transmit four-channel LED drive control signals.

[0008] The voltage regulator circuit is used to provide a stable voltage input for the SM16520P decoding chip.

[0009] As a further aspect of the present invention, the A and B signal pins of the SM16520P decoding chip are connected in series with overcurrent fuses.

[0010] As a further aspect of the present invention, a write line protection fuse is connected in series on the ADRI and ADRO input pins of the SM16520P decoding chip.

[0011] As a further aspect of the present invention: the voltage regulator circuit includes an MC33063 chip, an absorption circuit consisting of three varistors connected in a star configuration, and three parallel reverse diodes disposed at the voltage input terminal of the MC33063 chip, wherein the absorption circuit is connected to the voltage input terminal of the MC33063 chip.

[0012] As a further aspect of the present invention, the VIN pin of the MC33063 chip is connected to two external voltage monitoring resistors.

[0013] As a further aspect of the present invention: the red light driving circuit, green light driving circuit, blue light driving circuit and white light driving circuit all further include a step-down constant current LED controller formed by an inductor and two current sampling resistors, and a common mode inductor set at the input terminal of the LED string.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] The LED circuit of this invention is controlled by the SM16520P decoding chip. This chip provides parallel differential transmission for four LED drivers and is compatible with and expands upon the DMX512 (1990) signal protocol. It has a built-in 485 decoding module, strong anti-interference capability, and long transmission distance. In contrast, the single-chip microcomputer control method results in a more complex circuit, more peripheral components, and a longer debugging and development cycle. This solution is easier to control in terms of cost, and the produced products are of high quality and low price, resulting in good economic benefits.

[0016] The LED driver circuit chip of this invention is PT4121, which is a buck horizontal constant current controller operating in continuous inductor current conduction mode. Through a high-precision dimming resistor, the output current accuracy can reach ±3%. The maximum current of each channel is 3A.

[0017] This invention employs a high-efficiency DC-DC constant current drive. The PT4121 driver chip requires very few external components, achieving a single-chip efficiency of up to 97% and an overall circuit efficiency of 93%, a significant improvement over the 70% efficiency of previously used linear constant current solutions. Furthermore, the high efficiency results in low heat generation, allowing for a smaller heat dissipation area and a simpler, more aesthetically pleasing lighting fixture. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the control circuit structure in this invention.

[0019] Figure 2 This is a schematic diagram of the voltage stabilization power supply circuit in this invention.

[0020] Figure 3 This is a schematic diagram of the red light driving circuit in this invention.

[0021] Figure 4 This is a schematic diagram of the green light driving circuit in this invention.

[0022] Figure 5 This is a schematic diagram of the blue light driving circuit in this invention.

[0023] Figure 6 This is a schematic diagram of the white light driving circuit in this invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figures 1-6 In this embodiment of the invention, a differential parallel drive transmission RGBW constant current control circuit includes a voltage regulated power supply circuit, a control circuit, and a four-channel output constant current drive circuit. The control circuit is based on the SM16520P decoding chip and uses a 24V voltage input. Its A and B signal pins are connected in series with overcurrent fuses (F1 and F2) to provide overcurrent short-circuit protection. When the current exceeds the set current value, it will open the circuit for protection. A TVS diode (TVS1 and TVS2) is also connected in the input circuit to reduce the impact of voltage surge on the circuit when the light is turned on. When a surge occurs, a short circuit occurs, and the large voltage introduced into this component will not damage the subsequent circuit. When the voltage returns to normal, the high impedance (equivalent to an open circuit) circuit resumes normal operation, ensuring the stability of the differential signal input.

[0026] The ADRI and ADRO input pins of the chip are connected in series with write line protection fuses (F3 and F4) to protect the address write lines. When the circuit malfunctions or becomes abnormal, the current will continuously increase, and the increased current may damage some important or expensive components in the circuit. When the power rises abnormally to a certain level and temperature, the fuse will melt and cut off the current to prevent damage to the chip in case of a short circuit.

[0027] The SM16520P dedicated control chip is used for differential parallel transmission, employing the international DMX512 (1990) protocol. It supports a maximum of 1024 chips in parallel. The SM16520P's OUT port uses TTL drive output and is commonly used to control high-power drive transistors or constant current chips with dimming functions. During display control and address writing, the controller does not require four wires to the first LED; only the A / B signal lines are needed to complete address writing and display control. This eliminates the need for ground and address lines, greatly improving the flexibility and convenience of installation.

[0028] The voltage regulation power supply circuit uses the MC33063 chip with DC / DC converter as the control core of the buck converter device. It includes a reference voltage generator with automatic temperature compensation function, comparator, oscillator with controllable duty cycle, R-S flip-flop and high current output switching circuit, etc. The +5V voltage output provides a stable voltage power supply to the SM16520P parallel differential transmission four-channel LED driver output control chip.

[0029] The MC33063 chip's pin 5, VIN, monitors the output voltage via external resistors R1 and R2. The VIN voltage and the internal reference voltage of 1.25V are simultaneously fed into an internal comparator for comparison. When the VIN voltage falls below the internal reference voltage of 1.25V, the comparator outputs a switching voltage, activating the chip's internal trigger, which turns on the driver transistor ID1. This causes the output voltage to charge the output filter capacitor IEC2 to reach the set voltage. The output voltage setting formula is:

[0030] Uout = 1.25(1 + R2 / R1)

[0031] The voltage input section of the MC33063 chip includes a surge protection and spike absorption circuit consisting of three varistors connected in a star configuration (VDR3, VDR1, VDR2) and connected to GD1. When external interference suddenly generates a spike current or an overvoltage occurs at the 24V input, the circuit can conduct and shunt the current in a very short time, thereby preventing the surge from damaging the chip in the circuit.

[0032] Three reverse diodes (DD1, DD2, DD3) are connected in parallel at the 24V input terminal of the voltage input section of the MC33063 chip. The purpose is to use the unidirectional conduction characteristic of the diodes to prevent interference and damage to the circuit loop when the input is reversed.

[0033] The four-channel constant current drive circuit includes a red light drive circuit, a green light drive circuit, a blue light drive circuit, and a white light drive circuit. The red light drive circuit, the green light drive circuit, the blue light drive circuit, and the white light drive circuit all use the PT4121 chip as the core, and its VIN pin is connected to the PWM signal output terminal of the SM16520P.

[0034] Taking the red LED driver IC UR1 as an example, the PT4121, inductor LR1, and current sampling resistors RR1 and RR2 form a self-oscillating continuous inductor current mode buck constant current LED controller. Its maximum output current is calculated as follows:

[0035] Iout = 0.2 / [RR1*RR2 / RR1+RR2]

[0036] Furthermore, the LED's output current can be varied from 0% to 100% via the PWM signal output from the SM16520P. Its advantage lies in not altering the LED's color temperature.

[0037] DR1 is a fast recovery, low forward voltage drop, low parasitic capacitance, and low leakage Schottky diode, ensuring maximum efficiency and performance. A common-mode inductor LL2 precedes each group of PT4121 constant current drivers. The circuit integrates various high-frequency, digital, and analog circuits, which generate a large amount of high-frequency electromagnetic waves that interfere with each other during operation. This inductor filters out common-mode electromagnetic interference on signal lines and suppresses its own electromagnetic interference emissions, preventing interference with the normal operation of other chips in the same electromagnetic environment.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A differential parallel drive transmission RGBW constant current control circuit, comprising a voltage regulator circuit, a control circuit, and a four-channel output constant current drive circuit, characterized in that: The four-channel output constant current drive circuit includes a red light drive circuit, a green light drive circuit, a blue light drive circuit, and a white light drive circuit. The red light drive circuit, green light drive circuit, blue light drive circuit, and white light drive circuit all use the PT4121 driver chip as the core. The VIN pin of the PT4121 driver chip is connected to the PWM signal output terminal of the SM16520P decoding chip. The control circuit is based on the SM16520P decoding chip and is used to transmit four-channel LED drive control signals. The voltage regulator circuit is used to provide a stable voltage input to the SM16520P decoding chip. The voltage regulator circuit includes an MC33063 chip, an absorption circuit consisting of three varistors connected in a star configuration, and three parallel reverse diodes set at the voltage input terminal of the MC33063 chip. The absorption circuit is connected to the voltage input terminal of the MC33063 chip, and two voltage monitoring resistors are externally connected to the VIN pin of the MC33063 chip. The MC33063 chip's pin 5, VIN, monitors the output voltage via external resistors R1 and R2. The VIN voltage and the internal reference voltage of 1.25V are simultaneously fed into the internal comparator for voltage comparison. When the VIN voltage is lower than 1.25V, the comparator outputs a switching voltage, which turns on the chip's internal trigger, causing the driver transistor ID1 to conduct and charge the output filter capacitor IEC2 to reach the set voltage. The voltage input section of the MC33063 chip includes a surge protection and spike absorption circuit consisting of three varistors connected in a star configuration and connected to GD1. When external interference suddenly generates a spike current or an overvoltage occurs at the 24V input terminal, it can conduct and shunt the current in a very short time, thereby preventing the surge from damaging the chip in the circuit. The MC33063 chip has three parallel reverse diodes at the 24V input terminal of the voltage input section. The purpose is to use the unidirectional conduction characteristic of the diodes to prevent interference and damage to the circuit loop when the input is reversed. The A and B signal pins of the SM16520P decoding chip are connected in series with overcurrent fuses; when the current exceeds the set current value, it will open the circuit for protection; a TVS diode is also connected in the input circuit to reduce the impact of voltage surge on the circuit when the light is turned on. The SM16520P decoding chip has write line protection fuses connected in series on the ADRI and ADRO input pins to protect the address write lines. The red light driving circuit, green light driving circuit, blue light driving circuit, and white light driving circuit all include a step-down constant current LED controller formed by an inductor and two current sampling resistors, as well as a common mode inductor set at the input terminal of the LED string.

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