Patent ID: 8723833
Filing Date: 2014-05-13
Classification: G06F

Abstract:
1. A method for determining a user's touch in a capacitive touch sensor system having a plurality of sensors and a relaxation oscillator, comprising: performing a series of potential touch detection tests for the plurality of sensors until a potential touch is detected, wherein each potential touch detection test involves measuring a test frequency for one of the sensors, and wherein a potential touch is detected by detecting a deviation between the measured test frequency and a previously measured test frequency for the same sensor, wherein each potential touch detection test involves measuring the frequency of the relaxation oscillator for one of the sensors; and each potential touch detection test is performed twice, including operating the relaxation oscillator with a first drive current during a first potential touch detection test and with a second drive current during a second potential touch detection test; in response to detecting a potential touch, performing a series of baseline comparison tests for each of the sensors, wherein each baseline comparison test involves: determining whether any one of the sensors has been assigned a largest deviation value; and if one of the sensors has been assigned a largest deviation value, identifying that sensor as a touched sensor.