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Sampled-data interface circuit for capacitive sensors

  • US 5,661,240 A
  • Filed: 09/25/1995
  • Issued: 08/26/1997
  • Est. Priority Date: 09/25/1995
  • Status: Expired due to Fees
First Claim
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1. A sensing system comprising:

  • an integrator having an input and an output;

    a reference voltage source;

    a capacitive sensor comprising a plurality of capacitors;

    switching means connected to a said integrator, said capacitive sensor, and said voltage source for connecting said voltage source to said capacitive sensor to charge said capacitors with a charge, then for transferring said charge from said capacitors to said integrator, then for transferring said charge from said integrator to said capacitors, and then for outputting said charge as a voltage at said output of said integrator, wherein said voltage is a function of the capacitances of said capacitors; and

    a clock generator which is connected to said switching means, said clock generator controlling the timing of said connections made by said switching means and generating a non-overlapping clock with three phases.

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