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ADAPTIVE CAPACITIVE TOUCH SENSE CONTROL CIRCUIT

  • US 20090108914A1
  • Filed: 08/06/2008
  • Published: 04/30/2009
  • Est. Priority Date: 10/31/2007
  • Status: Active Grant
First Claim
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1. An adaptive capacitive touch sense control circuit, comprising a voltage buffer, a current setting resistor, a current mirror, a capacitor, a start comparator, an end comparator and a time-to-digital converter, with the voltage buffer being connected with the current setting resistor and the current mirror, the capacitor being connected with the current mirror, the start comparator and the end comparator, and the start comparator and the end comparator being connected with the time-to-digital converter, wherein the capacitor is connected with the current setting resistor;

  • the control circuit further comprises a latch provided with a first control switch between the capacitor and the current mirror and between the voltage buffer and the current setting resistor and a second control switch between the capacitor and the current setting resistor; and

    the current setting resistor is switched between the ground and a voltage source through a switching element, so that when the current setting resistor is grounded, the first control switch is closed and the second control switch is opened, and when the current setting resistor is connected with the voltage source, the second control switch is closed and the first control switch is opened.

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