发明授权
US06304091B1 Absolute position sensing by phase shift detection using a variable capacitor 有权
通过使用可变电容器进行相移检测的绝对位置检测

Absolute position sensing by phase shift detection using a variable capacitor
摘要:
A low-cost, high-resolution capacitive position sensor is provided using a variable capacitor. A vane moves parallel to a stator, where a dielectric is interposed between vane and stator, such that the vane overlaps at least a portion of the stator, creating a capacitance that varies as the vane moves relative to the fixed stator. The capacitor circuit outputs a signal having a phase shift relative to an input driver signal based on the relative positions of the vane and stator. The phase-shifted signal is used to derive the absolute position of the vane with respect to the stator. Two or more stator can be provided to provide two phase-shifted signals and a difference signal free of common mode effects. Enhanced embodiments include interdigitated stator portions for greater sensing resolution, and/or a two or three-pole filter to double or triple the dynamic range of the sensor.
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