WS2811A

WS2811A is a three-channel LED driver control IC. The chip integrates an intelligent digital interface with data latch, signal shaping, amplification and drive circuitry, along with a high-precision internal oscillator and a 20V high-voltage programmable constant-current output driver. To reduce power supply ripple, the OUTR, G, and B channels feature a staggered turn-on function that reduces circuit ripple during frame refresh. The chip uses a single-wire return-to-zero communication protocol. After power-on reset, the DIN pin receives data transmitted from the controller. The first 24 bits of incoming data are extracted by the first chip and latched into its internal data register; the remaining data is reshaped and amplified by the internal signal conditioning circuit, then forwarded through the DO pin to the next cascaded chip. Each chip in the chain extracts 24 bits from the signal. The chip employs automatic reshaping and forwarding technology, so the number of cascadable chips is not limited by signal integrity — only by signal transmission speed requirements. Based on the received 24-bit data, the internal data latch generates PWM signals with varying duty cycles on the OUTR, OUTG, and OUTB control outputs. When a RESET signal is received at the DIN pin, all chips simultaneously transfer their received data to the respective output segments. After the RESET signal ends, the chips begin accepting new data. Once the initial 24 bits are received, the data is forwarded via the DO pin. Prior to receiving a RESET code, the OUTR, OUTG, and OUTB pin outputs remain unchanged. Upon receiving a low-level RESET code of 280μs or longer, the chip outputs the 24-bit PWM data pulse widths received to the OUTR, OUTG, and OUTB pins. Available in SOP8 and FSOP8 packages.

Applications

• LED full-color luminous letter light strings, LED full-color modules
• LED full-color flexible/rigid light strips, LED guardrail tubes
• LED point light sources, LED pixel screens, LED custom-shaped screens
• Marquee lighting for various electronic products and electrical equipment
• Other various LED decorative lighting products

Key features

• OUTR, G, B port voltage tolerance 40V; DIN, DOUT voltage tolerance 30V
• Grayscale adjustment circuit (256-level adjustable)
• Built-in signal reshaping circuit — output signal is reshaped after reception at each IC, preventing waveform distortion accumulation along the line
• Built-in power-on reset and power-off reset circuit
• PWM control with 256-level adjustment, scan frequency 4KHz
• Serial cascade interface — data reception and decoding via single signal line
• Cascade count ≥1024 points at 30 frames/sec refresh rate
• Data transmission speed up to 800Kbps