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Methods and systems for detecting a capacitance using sigma-delta measurement techniques

  • US 7,683,641 B2
  • Filed: 10/15/2008
  • Issued: 03/23/2010
  • Est. Priority Date: 06/03/2005
  • Status: Active Grant
First Claim
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1. An electric circuit for measuring a capacitance value, the electric circuit comprising:

  • a first switch coupled to a first capacitance;

    an integrating capacitance coupled to the first capacitance, wherein the integrating capacitance is configured to accumulate charge received from the first capacitance;

    a charge changing circuit coupled to the integrating capacitance; and

    a controller configured to measure the capacitance value by repeatedly applying a voltage to the first capacitance using the first switch, repeatedly accumulating charge received from the first capacitance on the integrating capacitance, and repeatedly changing a charge on the integrating capacitance using the charge changing circuit in response to a voltage on the integrating capacitance being past a threshold of a quantizer.

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