• 一款适用于柔性显示AMOLED的触控芯片设计

    Design of a touch chip for flexible AMOLED displays

    • 柔性有源矩阵有机发光二极管(Active-Matrix Organic LightEmitting Diode,AMOLED)显示屏凭借其轻薄、可折叠及可卷曲的多样化形态,显著提升了用户使用体验,已成为高端便携电子产品的首选,并在车载显示等领域展现出广阔的应用前景。作为柔性显示模组的关键组成部分,柔性触摸屏因轻薄化设计导致对地负载电容与显示屏共模噪声显著增加,为触控芯片设计带来严峻挑战。针对上述问题,本文深入分析适用于柔性AMOLED显示屏的投射式电容触控芯片,并提出一种能够适应高负载、高噪声、高灵敏度场景的解决方案。所设计的电容触控芯片具有112个互容式触摸感应通道,采用180 nm CMOS工艺,驱动电压仅为3.3 V。在驱动方式上,采用并行驱动替代传统顺序驱动,显著提升响应效率。实际测试表明,该芯片信噪比(SNR)大于40 dB,报点率可达180 Hz,表现出优良的抗干扰性能与触控灵敏度。

       

      Abstract: Flexible active-matrix organic light-emitting diode (AMOLED) displays offer advantages such as lightness, foldability, and rollability, which significantly enhance user experience. They have become the preferred choice for high-end portable electronic devices and show promising application potential in areas such as automotive displays. As a key component of flexible display modules, flexible touch screens introduce significant challenges for touch controller design due to increased parasitic capacitance to ground and elevated display common-mode noise resulting from their ultra-thin structure. To address these issues, this paper investigates a projected capacitive touch controller suitable for flexible AMOLED displays and proposes a solution capable of operating under high capacitive load, high noise, and high sensitivity conditions. The designed touch controller integrates 112 mutual-capacitance sensing channels, fabricated in a 180 nm CMOS process with a driving voltage of only 3.3 V. It employs a parallel driving scheme instead of the conventional sequential driving approach, substantially improving the response speed. Experimental results demonstrate that the chip achieves a signal-to-noise ratio (SNR) greater than 40 dB and a report rate of 180 Hz, exhibiting excellent noise immunity and touch sensitivity.

       

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