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.

中文翻译：

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液晶显示器中Mini-LED背光的AM PWM驱动电路

这项工作提出了一种微型LED驱动电路，该电路采用了脉宽调制（PWM）驱动方法，用于液晶显示器（LCD）背光。所提出的电路可以补偿阈值电压（ $ \ text {V} _ {\ mathrm {TH}} $ 低温多晶硅薄膜晶体管（LTPS TFT）的变化和VSS电流电阻（IR）的上升，从而产生稳定的驱动电流来为mini-LED供电。由于所提出的电路使用PWM方法，因此mini-LED可以在最佳的亮度效率点工作，从而将电路的功耗降至最低。测量所制造的LTPS TFT的电学特性以建立仿真模型，以证明所提出电路的可行性。仿真结果表明，当小型LED的相对电流误差率低于9％时， $ \ text {V} _ {\ mathrm {TH}} $ 电压变化±0.3 V，VSS上升1V。就精确控制灰度而言，电流脉冲的时移在整个灰度范围内在11.48 us之内。与由脉冲幅度调制驱动的电路相比，所提出的电路的功耗改善超过21％。