静电电容式触摸检测技术

Technology basis of capacitive touch detection

本文主要介绍了瑞萨电子的静电电容式触摸检测技术,包括触摸开关检测的基本原理和抗干扰技术。其中,触摸原理部分介绍了静电电容—电流转换原理、电流的数值化及开关判定;触摸技术的难点——抗干扰技术部分介绍了硬件实现的移相技术和扩频技术,以及由软件实现的漂移校正技术和平滑处理技术。

This paper mainly focuses on Renesas＇ capacitive touch detection technology research, including the basic principles of touch-key detection and the noise immunity technology. The section of touch- key detection principles introduces the capacitance value - current conversion theory, the current digitalization and the touch-key ON/OFF determination. The section of noise immunity technology introduces the phase shifting technology and the spread spectrum technology implemented by hardware, as well as the software drift correction technology and the software smoothing technology.