WS2801constantcurrentLEDdriver-AdafruitIndustries.pdfVIP

Preliminary WS2801 3-Channel Constant Current LED Driver With Programmable PWM Outputs 　 Features 　 Applications ? Supports both constant voltage and constant current drive mode ? LED decorative lighting ? Programmable constant LED drive current ? Indoor/Outdoor LED video or massage display ? Wide constant output current range 5~150mA ? PWM signal generator ? Build in PWM dimming scheme for each output channel, ? LCD TV back lighting supports free-run, especially suitable for low cost controller application ? PWM free-run capability(refresh rate(2.5KHz) ? Build in buffers to cascading data and clock to the next driver ? Output polarity reverse function ? Support hot swap ? Maximum input clock frequency 25MHz ? Power supply voltage 3.3~5.5V 　 General Description The WS2801 is a constant current LED driver. It is designed for indoor/ outdoor LED displays and decorative LED lighting system. It is suitable for LED cascading applications. The WS2801ownes 3 output channels, each channel can drive a constant current up to 30mA. WS2081 contains serial shift registers, data latches, output registers, band gap reference voltage generator, internal oscillator, and programmable constant output current drivers. The serial data is read into the shift registers at the rise edge of the external clock. The data and clock output buffers are designed for cascading another chip. The output polarity reverse function is designed for driving high power LED by adapting the application circuitry. The WS2801 adopts the reliable 2-wire scheme, which features low EMI transport, very strong anti-interference ability, and support hot-swap. The 2-wire control scheme can reduce the system cost; it is very suitable for low cost LED decorative LED lighting systems. WS2801 is available in both SOP-14 and DIP-14 packages, the operating temperature is -40~85℃ 　 Pin Configurations 　 　 Typical Application Circuit Fig1.a SOP-14 package 　 Fig1.b DIP-14 package WS-Preliminary-V0.3 1 /15 Preliminary WS2801 3