关键词: LED, 驱动芯片, OS-PWM算法

Abstract: For the sake of solving the problems of the fine pixel pitch LED display screen,such as the low refresh rate,low grayscale,pitting,the first line of dark,open road cross,following ghost and other phenomena,an OS-PWM algorithm based on traditional PWM algorithm is presented in this paper.Besides,a LED driver IC is designed based on this algorithm.First of all,to solve the problems of low refresh rate and low gray scale,the whole display cycle is evenly scattered by OS-PWM algorithm,and the refresh rate is improved without affecting the total gray scale.Secondly,aiming at pitting phenomenon,the registration optimal design was added to enhance the display effect of low gray scale.And then,the reverse counting method is adopt to solve the first line of dark problems,and the reserved time makes the capacitor discharge ahead of time,which is helpful to improve this problem.Finally,open detection circuit is built-in for the open road cross phenomena,fundamentally shield this problem.The experimental results show that the design is correct and reasonable.

Key words: LED, driver IC, OS-PWM algorithm