AM PWM Driving Circuit for Mini-LED Backlight in Liquid Crystal Displays

IEEE Journal of the Electron Devices Society

Chia-En Wu¹  Jia-Tian Peng¹  Chih-I Liu²  Chieh-An Lin²  Ming-Yang Deng²  Yuan-Hao Ho²  Chih-Lung Lin²  Chia-Ling Tsai²  Sung-Chun Chen²  Wei-Sheng Liao² 

[1] Circuit Design Department, AU Optronics Corporation, Hsinchu, Taiwan;Department of Electrical Engineering, National Cheng Kung University, Tainan, Taiwan;

关键词: Active-matrix display;    LCD backlight;    high dynamic range;    mini-LED;    pulse-width modulation;    power consumption;   

DOI  :  10.1109/JEDS.2021.3065905

来源: DOAJ

【 摘 要 】

This work proposes a mini-LED driving circuit that adopts the pulse-width modulation (PWM) driving method for use in a liquid-crystal display (LCD) backlight. The proposed circuit can compensate for the threshold voltage ( $\text{V}_{\mathrm{ TH}}$ ) variation in a low-temperature poly-crystalline silicon thin-film transistor (LTPS TFT) and a VSS current-resistance (I-R) rise, to generate a stable driving current to power the mini-LED. Since the proposed circuit uses the PWM method, the mini-LED can be operated at the best luminance-efficacy point, minimizing the power consumption of the circuit. The electrical characteristic of fabricated LTPS TFTs are measured to establish a simulation model to demonstrate the feasibility of the proposed circuit. Simulation results demonstrate that the relative mini-LED current error rates are below 9% when the $\text{V}_{\mathrm{ TH}}$ varies ± 0.3 V and VSS rises by 1 V. With respect to precise control of the gray level, the time shifts of current pulses are within 11.48 us over the whole grayscale. The improvement in the power consumption of the proposed circuit is more than 21% than that of a circuit that is driven by pulse amplitude modulation.

【 授权许可】

Unknown