Abstract: Based on the CSMC 0.5μm standard CMOS technology,designed a constant LED driver with disordered PWM control.The chip use disordered PWM technology to improve the LED refresh rate,use PWM synthesis technology to improve the LED grayscale, use constant current driving technology to reduce the LED light -declining.At 3V~5.5V supply voltage,-40℃~85℃,the circuit was simulated on Cadence spectre,the results show that following the input image data,LED refresh rate improved greatly;PWM synthesis model achieved 14 bits grayscale;dot correction mode achieved 6-bit chrominance correction;output current error accuracy is ±5%.