×

Capacitance detecting apparatus and capacitive touch control system using the same

  • US 8,704,586 B2
  • Filed: 08/13/2012
  • Issued: 04/22/2014
  • Est. Priority Date: 03/05/2012
  • Status: Active Grant
First Claim
Patent Images

1. A capacitance detecting apparatus, coupled to a capacitor to be measured, the apparatus comprising:

  • a first capacitor and a second capacitor, coupled to the capacitor to be measured via an input node;

    a control module, for providing a first voltage-drop variation to the first capacitor and a second voltage-drop variation to the capacitor to be measured to introduce a third voltage-drop variation to the second capacitor;

    wherein the first voltage-drop variation and the second voltage-drop variation cause charge flowing from the first capacitor to the input node to have a same sign with charge flowing from the input node to the capacitor to be measured; and

    a judging module, for determining capacitance of the capacitor to be measured according to capacitance of the first capacitor, capacitance of the second capacitor, the first voltage-drop variation, the second voltage-drop variation and the third voltage-drop variation,wherein the capacitor to be measured is connected to the capacitance detecting apparatus via a connecting wire formed on a circuit board, the circuit board has a shielding layer, and the first capacitor comprises parasitic capacitance between the connecting wire and the shielding layer, and the control module controls the shielding layer to provide the first voltage-drop variation of the first capacitor.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×