WS2811M

WS2811 is a three-channel LED driver control IC. It integrates a smart digital interface, data latch, signal reshaping and amplification driver circuit, along with a high-precision internal oscillator and a 20V high-voltage programmable constant-current output driver. To reduce power supply ripple, the 3 channels feature a staggered turn-on delay, which helps minimize circuit ripple during frame refresh. The chip uses single-wire return-to-zero (RZ) communication. 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 stored in its internal data latch. 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 data stream. The chip employs automatic reshaping and forwarding technology, so the number of cascadable chips is not limited by signal degradation — only by signal transmission speed requirements. Based on the received 24-bit data, the internal data latch generates PWM signals with different duty cycles on the OUTR, OUTG, and OUTB control outputs. When a RESET signal is received at the DIN pin, all chips simultaneously transfer the received data to their respective output stages. After the RESET signal ends, the chip begins accepting new data. Once the initial 24 bits are received, the remaining data is forwarded through 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 just received to the OUTR, OUTG, and OUTB pins. Available in SOP8 and MSOP8 packages.

Applications

• LED full-color illuminated sign light strings, LED full-color modules
• LED full-color flexible/rigid light strips, LED guardrail tubes
• LED point light sources, LED pixel screens, LED irregular-shaped screens
• Running light effects for various electronic products and electrical equipment
• Other various LED lighting decorative products

Key features

• R, G, B output port withstand voltage 20V, DIN port withstand voltage 9.5V
• Built-in voltage regulator; for power supplies below 24V, only a series resistor to the ICVDD pin is required — no external voltage regulator needed
• Grayscale adjustment circuit (256-level adjustable grayscale)
• Built-in signal reshaping circuit; each IC reshapes the received signal before output, preventing accumulated waveform distortion along the line
• Built-in power-on reset and power-down reset circuits
• PWM control enables 256-level adjustment with a scan frequency of 2KHz
• Serial cascade interface; data reception and decoding via a single signal line
• Transmission distance up to 5 meters between any two points with no additional circuitry required
• Cascade count no less than 1024 nodes at a refresh rate of 30 frames/second
• Data transmission speed up to 800Kbps