Capacitance measuring apparatus and method,申请号EP20050019336-传众专利搜索

Capacitance measuring apparatus and method

申请公布号：EP1635147(A2)

申请号：EP20050019336

申请日期：2005.09.06

申请公布日期：2006.03.15

申请人：

OMRON CORPORATION

发明人：KINOSHITA, MASAHIRO;URATA, HIDEYUKI;TSUGUI, HIDESHI;TANABE, YOSHIHIRO

分类号：G01D5/24;G01R27/26;H03K17/96

主分类号：G01D5/24

摘要：<p>Whether a human body is touching or not is detected highly accurately at high speed. Switch SW1 is turned on to charge condenser Ca by power supply Vcc. The switch SW1 is turned off to transfer the electric charge charged in the condenser Ca to condensers Cs and Cx. The switches SW2 and SW3 are repeatedly turned on and off for a predetermined short time, and thus the electric charge charged in the condenser Ca is slowly discharged through resistor R. The unknown charging voltage Vx of the condenser Cx is compared with the reference voltage Vref by comparator Comp, and the unknown capacitance of the condenser Cx is computed based on the number of times to count turning on and off until it is smaller than the reference voltage Vref. When the computed unknown capacitance of the condenser Cx is the value near the capacitance of a human body, it is determined that a human body is touching. The invention can be applied to a touch sensor.</p>