A 6.9mW 120fps 28×50 Capacitive Touch Sensor with 41.7dB SNR for 1mm Stylus Using Current-Driven ΔΣ ADCs

📋 论文概要

本文提出一种用于电容触摸传感器的电流驱动ΔΣ ADC架构，实现了6.9mW功耗、120fps帧率和28×50分辨率，针对1mm触控笔达到41.7dB SNR，解决了细间距触摸屏对高分辨率、低功耗和高效率的需求。

💡 主要创新点

• 采用电流驱动ΔΣ ADC替代传统电容电荷放大器作为模拟前端，改善了噪声性能并降低了功耗。
• 实现了高帧率（120fps）和低功耗（6.9mW）的平衡，同时保持对1mm触控笔的高信噪比（41.7dB）。

🏷 关键词

📄 原文摘要

Capacitive touch sensors are essential for the user interfaces of smartphones and tablet PCs. Large touch-screen panels (TSPs) require high-quality touch features, resulting in an increased number of sensing channels as well as a reduction of sensing capacitance due to fine-pitch arrangements. Therefore, touch-sensor ICs demand high resolution, low power and high efficiency. State-of-the-art capacitive touch sensors [1-6] mostly rely on capacitive charge amplifiers as analog frontends (AFEs), which convert the capacitor change into a voltage signal and often limit the system noise figure, thus consuming most of the power. This paper presents a 120fps 28×50 touch sensor that achieves 41.7dB SNR for 1mm-φ stylus, while consuming 6.9mW, which results in an energy efficiency of 0.41nJ/step, for a >4× improvement compared to state-of-the-art stylus touch sensors (see Fig. 9.7.6). This is achieved by a current-driven ΔΣ ADC architecture,

👥 作者与机构

Hyunseok Hwang1, Hyeyeon Lee1, Hongchae Kim2, Youngcheol Chae1

Yonsei University, Seoul, Korea, 2TRAIS, Ansan, Korea