Design Of LED Display Driver Chip

In recent years, LED display becomes more and more popular and developments from the static monochrome display to the dynamic color display. The huge change is attributed to a variety of color of LED and the development of the display driver IC chip. At the beginning, general driver chip which was used in monochrome displays showed up, but it couldn’t meet the quality requirements of color dynamics display. Then the dedicated LED display driver chip turned up.In this paper, a dedicated LED display driver chip with16constant-current output channels and SPWM grayscale processing module built in is mentioned, which can display16bits65536grayscales. The difference of driver currents between different chips or between different channels of a certain chip is small that ensures the good display quality of the LED display.The analog part of the chip using a fashionable chopper modulation technique to generate a stable reference voltage and current ensures the stability of output current. The use of power MOSFET ensures the range of output current and the driving capability of the chip. The digital part of the chip with the status register built in makes it programmable, which broadens the application field of the chip, and the built-in SWPM function enhances the ability of gray scale controlling.Finally, the chip was taped with the SMIC35bcd₂430process and packaged with SSOP24standard. A programmed AVR SCM produced the excitation signals for testing the product. From the test results, it is found that the chip works and the design works.