The two-lane 18-channel programmable constant-current LED driver IC with PWM

Characteristic range of applications

● 18-bit constant current output. ● LED guardrail lamp

● output current does not change with the driver stage output voltage change. ● indoor / outdoor LED display / take the word of screen

● chip operating voltage of 3.3 ~ 5.5V.

● can withstand up to 40V output voltage of the output driver stage.

● 8-bit PWM grayscale control, single-channel independent display 256 grayscale.

● the 2.5KHz grayscale data refresh frequency.

● extremely accurate output current accuracy:

Between the channel and the channel within the same chip, precision: ± 1%;

Output current accuracy between the different chips: ± 2%;

● maximum input data clock frequencies up to 25MHz.

● have a free run ability, grayscale data written after the chip according to grayscale.

● Data and automatically adjust the output, without having to do the other controls.

● staggered time delay between the output channels.

● Schmitt Trigger input.

● over-temperature protection.

 

Typical internal block diagram

 

Figure 1. The WS2803 internal block diagram

 


Description

The WS2803 is a constant current output of the LED driver, mainly for indoor and outdoor LED display, take the word screen and LED decorative lighting systems. It is ideal for applications requiring a cascade of occasions, such as display, take the word of screen and LED guardrail lamps, and other applications. WS2803 has 18 output channels, each channel can output up to 30mA constant current. The chip contains 144 internal serial shift register, data latches, the bandgap voltage reference, internal oscillator and high-voltage programmable constant current output driver stage.

The input serial data shift register, the rising edge of clock signal CKI into the chip when data entry is complete, the chip automatically according to the input grayscale data to output the PWM constant current. Data and clock output buffer is designed for cascading other WS2803 chip. WS2803 constant output current to ground resistors to set the one in the IREF pin.

WS2803 built-in overtemperature protection, when the chip internal temperature reaches 150 ℃ when the chips can automatically shutdown the output, since the chip temperature will drop when the temperature dropped to 125 ° C, the WS2803's output will be enabled.

WS2803 provides two kinds of package and DIP-28 SOP-28, its temperature range of -40 ~ 85 ℃

 

Download of documents:

 

 

WS2803 Specification book