Low-Power, High-Performance, and Highly Reliable EM Gate Driver Circuit Using LTPO Technology for Mobile Displays

초록

This article presents a compact, low-power, and high-performance pulsewidth-modulated (PWM) row driver circuit designed for high-resolution active-matrix organic light-emitting diode (AMOLED) displays, leveraging low-temperature polycrystalline silicon and oxide thin-film transistors (LTPO TFTs). The proposed 11T3C structure eliminates output intermediate voltage transitions and supports a wide range of variable refresh rates (VRRs) from 1 to 120 Hz, while minimizing both static and dynamic power consumption. A key innovation lies in the robust handling of oxide TFT threshold voltage variations using a bootstrapped control scheme that ensures stable turn-off behavior under stress-induced degradation. The proposed driver achieves fast transition times ( 1.01 mu s rising and 1.56 mu s falling) and maintains stable output across a 14 V swing, even under oxide V-TH shifts from -7 to + 7 V. Power consumption was measured to be 4.35 mW at 1 Hz and 8.98 mW at 120 Hz for 1600 driver stages (3200 channels), demonstrating significant power reductions compared to conventional circuits. Full-panel measurements on a 6.81-in QHD AMOLED display demonstrate superior performance in terms of power and reliability compared to prior art, and were validated through industry-level qualification testing, supporting its suitability for ultralow-power displaysystems.

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