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 ( VTH\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 VTH\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 Mini-LED 背光的 AM PWM 驱动电路


这项工作提出了一种采用脉宽调制（PWM）驱动方法的迷你LED驱动电路，用于液晶显示器（LCD）背光。所提出的电路可以补偿低温多晶硅薄膜晶体管（LTPS TFT）中的阈值电压（VTH\text{V}_{\mathrm{TH}}）变化和VSS电流电阻（ IR）上升，产生稳定的驱动电流为mini-LED供电。由于该电路采用 PWM 方法，因此 mini-LED 可以在最佳亮度效率点运行，从而最大限度地降低电路功耗。测量制造的 LTPS TFT 的电气特性，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VTH\text{V}_{\mathrm{TH}}变化±0.3V且VSS上升1V时，相对mini-LED电流误差率低于9%。灰度级中，整个灰度级上电流脉冲的时移在 11.48 us 以内。与脉冲幅度调制驱动的电路相比，所提出的电路的功耗改善了21%以上。