WS2818
Single-line 256 Gray-level 3-channal
Constant Current LED Driver IC
Features
12V/24V available, that work on different applications of stable pressure.
Built-in voltage regulator tube, only add a resistance to IC VDD pin when the voltage is below DC24V.
Adopts the built-in signal reshaping circuit to achieve the signal waveform shaping, and thus no signal waveform
distortion takes place.
Built-in power-on reset and brown-out reset circuits.
The gray levels of each pixel of 256 levels, and the refresh frequency reaches to 2KHz/s.
Serial cascading interface, data receiving and decoding are all achieved by one signal line.
Signal Break-point Continuous Transmission, any pixel’s failure, it won’t affect the whole display effect.
The distance of any two signal transmission points is less than 5 meters, there’s no extra circuits needed.
When the refresh rate of 30fps, the cascade number are not less than 1024 pixels.
Send data at speeds of 800Kbps.
Good consistency reliability, high cost-effective.
Applications
Guardrail tube series, point light display series, flexible/rigid strips series, module series applications.
Lighting stage costumes, innovative gadgets or any other electronic products.
General description
WS2818 is a 3-channel LED driver control circuit, its internal include intelligent digital port data latch and signal
reshaping amplification drive circuit. Also include a precision internal oscillator and a 12V voltage programmable
constant current control part, which achieves highly consistent color effect.
WS2818 has strong features in Signal Break-point Continuous Transmission, it adopts dual signal transmission,
these signals are able to work together without interaction. The user can select the first chip DIN/BIN as the control
signal input pin, and the follow-up cascade chips will automatically identify the output signal released by the first chip
which not to affect the whole display effect.
WS2818 adopts Single-line Return-to-Zero communication protocol. After the chip gets power-on reset, the DIN port
receive data from controller, the first chip collects initial 24bit data then sent to the internal data latch, the other data
which reshaping by the internal signal reshaping amplification circuit sent to the next cascade pixel through the DO port.
The data reduced 24bit after transmitted through every pixel. Since WS2818 adopts auto-reshaping transmit technology,
making the pixel cascade numbers are not limited to the signal transmission, but to signal transmission speed. When BIN
works as control signal receiving interface, its control data is 24bit more than the DIN interface, so as to ensure that the
two ways to control the number of pixels is the same
Based on the received 24bit data, the internal data latch generates different duty cycle control signals in the OUTR,
OUTG, OUTB port. All chips synchronous send the received data to each segment when the DIN port input a reset signal.
It will receive new data again After the reset signal finished. Before a new reset signal received, the control signal of
OUTR, OUTG, OUTB pin unchanged. The chip exports PWM data to OUTR, OUTG, OUTB pins, after receive a low
voltage reset signal the time retain over 300us.
SOP8, DIP8 and MSOP8 packaging available.
http://www.world-semi.com/en
