METHODS AND SYSTEMS FOR DETECTING A CAPACITANCE USING SIGMA-DELTA MEASUREMENT TECHNIQUES

摘要

Methods, systems and devices are described for detecting a measurable capacitance (Cx) using sigma-delta measurement techniques. According to various embodiments, a voltage is applied to the measurable capacitance (Cx) using a first switch. The measurable capacitance is allowed to share charge with a passive network. If the charge on the passive network (109) is past a threshold value, then the charge on the passive network (109) is changed by a known amount for a sufficient number of repetitions until the measurable capacitance (Cx) can be detected. Such a detection scheme may be readily implemented using conventional components, and can be particularly useful in sensing the position of a finger, stylus or other object with respect to a button, slider, touchpad or other input sensor.