CXLE87211A is a dedicated LED driver chip that integrates MCU digital interface, data latch, and four-way constant current drive circuit. It supports independent control of the four LED channels OUTW, OUTR, OUTG, and OUTB by inputting a set of data containing constant current settings and PWM dimming through an external controller. The chip is equipped with a built-in 5V voltage regulator, and the peripheral circuit is simple. It supports a wide voltage input of 6-24V and is widely used in various LED decorative lighting products.
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[ CXLE87211A ]"
There is a continuous demand for the flexibility, accuracy, and cost-effectiveness of driver chips in LED decorative lighting and control systems.CXLE8721As a four channel LED constant current adjustable driver IC, 1A relies on its unique current grading adjustment capabilitystableThe single line cascading characteristics and excellent output consistency provide a cost-effective solution for low to medium speed LED applications such as guardrail tubes and point light sources. This article will comprehensively analyzeCXLE8721The technical features, communication protocol, and typical applications of 1A assist engineers in buildingstableReliable LED driver system.
1、 Chip Overview
CXLE87211A is an integrated MCU digital interface, data latch, and four-wayconstant current driveSpecialized for circuitsLED driver chipIt supports inputting a set of constant current settings through an external controllerPWM dimmingThe data enables independent control of the four LED channels OUTW, OUTR, OUTG, and OUTB. The chip is equipped with a built-in 5V voltage regulator, and the peripheral circuit is simple, supporting 6-24VWide voltage inputWidely used in various LED decorative lighting products.
2、 Core functional features
• Four channel independent outputSupport WRGB four channel constant current output, each channel can independently set current and PWM.
• 64 level constant current adjustableThe output current of each channel can be precisely adjusted between 6.5mA and 38mA, with a total of 64 levels.
• 256 levelsPWM dimmingSupport high-precision brightness control to achieve smooth brightness changes.
• High precision outputThe current error between channels shall not exceed± 3%, with inter chip error not exceeding± 5%.
• Single line serial cascadeSupport automatic shaping and forwarding, signal transmissionstableThere is theoretically no limit to the number of cascades.
• Built in 5V voltage regulatorVDD has a built-in voltage regulator, simplifying the design of peripheral power supplies.
• SOP8 encapsulationSmall size, suitable for high-density PCB layout.
3、 Electrical characteristics and working conditions
CXLE87211A has reliable electrical performance:
• The OUT port has a voltage resistance of up to 32V and is suitable for various LED series structures.
• The working temperature range is -40 ℃ to+85 ℃, suitable for outdoor and industrial environments.
• The data transmission rate is 200KHz, suitable for medium and low-speed display systems.
• The typical static current value is 2.8mA, and the power consumption control is good.
4、 Communication Protocol and Data Format
The chip adopts single line zeroing code communication, and each frame of data contains:
• C1/C2 commandUsed to set constant current values for four channels, with 6 bits of data for each channel, supporting 64 level adjustment.
• Dn commandUsed to set the PWM duty cycle of each channel, 8-bit data, supports 256 levels of dimming.
• Reset signalHigh level active, used to trigger data validation and system reset.
The chip starts forwarding subsequent data after receiving 32-bit data, achieving seamless cascading. The controller only needs to send C1/C2 and multiple sets of Dn data once to configure and refresh the entire link.
5、 Typical Application Design Guidelines
5.1. Cascade and refresh rate calculation
The system refresh rate is directly related to the number of pixels. Taking 200KHz communication rate as an example:
• Each pixel (WRGB) requires the transmission of 32-bit PWM data, which takes 160μ s.
• If the system contains 1000 pixels, with a single refresh time of 160ms and a refresh rate of 6.25Hz, it is suitable for static or slow dynamic display scenes with low refresh rate requirements.
5.2. Power configuration and resistor selection
Configure VDD series resistance based on power supply voltage (DC):
• 6V power supply is recommended to be connected in series with 50Ω Resistance;
• It is recommended to connect a 12V power supply in series with 650 Omega; Resistance;
• 24V power supply is recommended to be connected in series with 1.8kΩ Resistance.
5.3. Constant current optimization and heat dissipation management
To ensure optimal operation of the chip, it is recommended to control the OUT port voltage between 1.2V and 3V. Excessive voltage will lead to increased power consumption and severe heating of the chip, affecting the system's lifespan. Voltage regulation can be achieved in the design by connecting resistors in series or optimizing the LED series connection method.
5.4. Expansion plan
If a larger driving current is required, multiple OUT ports can be connected in parallel. For each parallel connection, the maximum output current increases by 38mA, and after four full parallel connections, the maximum output current can reach 152mA. This method requires software cooperation to set multiple sets of register values separately to achieve precise current control and high brightness driving.
6、 TypicalApplication Circuit
CXLE87211A is suitable for low-speed applications such as guardrail tubes, point light sources, LED subtitle screens, etc. Attention should be paid to:
• Connect 100Ω in series with DIN/DO pins; Resistors to prevent damage from hot swapping;
• Connect a 104 capacitor between VDD and GND, and try to be as close to the chip pins as possible to enhance the systemstableSex;
• Signal lines should be properly shielded to avoid interference issues during long-distance transmission.
7、 Constant current performance and curve analysis
CXLE8721Under the same constant current setting, the current difference between channels and chips is extremely small for 1A. The constant current curve shows that when the OUT port voltage exceeds 0.8V, it enters the constant current zone, and the output current basically does not change with the voltage,stableExtremely high performance, suitable for WRGB lighting systems that require strict color consistency.
8、 Packaging and Pin Function
Nine,Conclusion
CXLE87211A with its four channel independent control, 64 level adjustable current, high-precision output, andstableThe cascading ability has shown outstanding performance in the field of medium and low-speed LED decorative lighting and control. Whether it's static color display or simple dynamic effects, it can provide reliable hardware support. JTMIC（jtm-ic.com）As the official technical partner of this chip, we provideSample RequestA one-stop service from technical guidance to bulk supply.
For detailed data manuals, design tools, or sample support, please visit the JTMIC official website or contact our technical team.
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