Methods and circuits for measuring mutual and self capacitance

摘要

In an example embodiment, an apparatus includes a sensing device. The sensing device includes circuitry configured to sense self-capacitance and circuitry configured to sense mutual-capacitance, each configured to detect capacitance values corresponding to whether an object is proximate to a touch screen. The sensing device is configured to measure a first capacitance value using the self-capacitance circuitry during self-capacitance sensing operations and to measure a second capacitance value using the mutual-capacitance circuitry during mutual-capacitance sensing operations.

主权项

1. An apparatus comprising:
a sensing device coupled to a capacitive sense array including a plurality of capacitive sensors, wherein each capacitive sensor of the capacitive sense array includes a respective self capacitance component and a respective mutual capacitance component, and the sensing device further comprises: self-capacitance circuitry electrically coupled to the respective self capacitance component of each capacitive sensor and configured to perform self-capacitance sensing operations to measure self capacitance of the respective capacitive sensor; and mutual-capacitance circuitry electrically coupled to the respective mutual capacitance component of each capacitive sensor and configured to perform mutual capacitance sensing operations to measure mutual capacitance associated with the respective capacitive sensor; wherein both the self-capacitance circuitry and the mutual-capacitance circuitry are coupled to each capacitive sensor by a respective single pair of electrodes associated with the respective capacitive sensor, and configured to detect whether an object is proximate to a touch screen by measuring the self and mutual capacitances of the respective capacitive sensor independently and simultaneously.