Capacitance sensor

US7944216B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Georg Brasseur · Wien, AT
• Thomas Bretterklieber · Lieboch, AT
• Dirk Hammerschmidt · Villach, AT
• Gert Holler · Graz, AT
• Tobias Werth · Villach, AT
• Hubert Zangl · Graz, AT

Key dates

• Filing date: Dec 5, 2008
• Grant date: May 17, 2011
• Expiry date: Jul 29, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/2405
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A capacitance sensor, having at least one electrode is disclosed. A frequency spread signal generation circuit is coupled to the at least one electrode to apply a frequency spread signal based on a spread sequence. A periodic signal with a frequency is coupled to the at least one electrode. A frequency controller is coupled to the frequency spread signal generation circuit to vary the frequency of the periodic signal. A receiver circuit is coupled to the at least one or a further electrode to receive a version of the frequency spread signal which depends on a capacitance applied to the at least one electrode. An evaluation circuit is coupled to the receiver circuit to determine a capacitance value based on the received, dependent version of the frequency spread signal.