Capacitance detecting apparatus and capacitive touch control system using the same
First Claim
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.
2 Assignments
0 Petitions
Accused Products
Abstract
A capacitance detecting apparatus, coupled to a capacitor to be measured, includes a first capacitor, a second capacitor, a control module and a judging module. The first and second capacitors are coupled to the capacitor to be measured via an input node. The control module provides 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. The first and second voltage-drop variations cause charge flowing from the first capacitor to the input node have a same sign with charge flowing from the input node to the capacitor to be measured. The judging module determines capacitance of the capacitor to be measured according to capacitance of the first and second capacitors as well as the first, second and third voltage-drop variations.
7 Citations
12 Claims
-
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; anda 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 Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A capacitive touch control system, comprising:
-
a display device; a plurality of sensing capacitors, respectively corresponding to a plurality of physical positions on the display device; a first capacitor and a second capacitor, coupled to one of the plurality of sensing capacitors via an input node;
wherein the one sensing capacitor is a capacitor to be measured;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 incur a third voltage-drop variation of 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; anda 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 first capacitor and second capacitor are coupled to the capacitor to be measured via a connecting wire formed on a circuit board, the circuit board comprises a shielding layer, the first capacitor comprises a 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 Dependent Claims (8, 9, 10, 11, 12)
-
Specification