公开(公告)号：US20060092032A1

公开(公告)日：2006-05-04

申请号：US10978260

申请日：2004-10-30

申请人： Gregory Manlove ,  Robert Constable ,  Ashraf Kamel ,  Gregory Cobb ,  Duane Fortune ,  William Fultz ,  Dennis Griffin ,  Thomas Voreis

发明人： Gregory Manlove ,  Robert Constable ,  Ashraf Kamel ,  Gregory Cobb ,  Duane Fortune ,  William Fultz ,  Dennis Griffin ,  Thomas Voreis

IPC分类号： G08B21/00

CPC分类号： G01L1/144 ,  B60N2/002

摘要： The capacitance of a shielded capacitive load cell is determined so as to minimize the effect of stray or parasitic capacitance between the load cell and other objects including the shield. The load cell conductors are coupled across input and output terminals of an operational amplifier that is tied to a reference voltage. A constant current is applied to the load cell, and the resulting rate of change in voltage at the amplifier output is measured as a representation of the load cell capacitance. In a vehicle seat sensor application including an electromagnetic interference shield between the load cell and the seating surface, the amplifier output is coupled to the load cell electrode furthest from the shield, the amplifier maintains the other load cell electrode at a virtual reference voltage, and the shield is tied to the reference voltage.