EXPANDED ELECTRODE GRID OF A CAPACITANCE SENSITIVE TOUCHPAD BY USING DEMULTIPLEXING OF SIGNALS TO THE GRID AS CONTROLLED BY BINARY PATTERNS FROM A TOUCH SENSOR CIRCUIT

摘要

A demultiplexer disposed between a touch sensor circuit and electrodes of a touchpad electrode grid, wherein instead of using the touch sensor circuitry to directly drive each electrode, the touch sensor circuitry instead transmits control signals to the demultiplexer, wherein the control signals instruct the demultiplexer to select a subset of the plurality of electrodes to be driven, and thereby perform object detection and tracking, wherein by using the demultiplexer to drive electrodes, a much greater number of electrodes can be driven by the touch sensor circuit, thereby increasing the effective size of a touchpad that can be controlled by the touch sensor circuitry (see figure 3).