Touch panel sensing circuit
First Claim
1. A touch panel sensing circuit for sensing a voltage variation of a coupling capacitor formed between a first directional signal line and a second directional signal line separated from the first directional signal line when an object approaches, the touch panel sensing circuit comprising:
- an input voltage source for producing a plurality of periodic voltage cycles;
a first voltage switch having a first terminal connected to the input voltage source and a second terminal connected to the first directional signal line;
a common voltage source for providing a DC common voltage;
a second voltage switch having a first terminal connected to the common voltage source and a second terminal connected to the first directional signal line;
a first switch having a first terminal connected to the second directional signal line;
an amplifier having an inverting input terminal connected to a second terminal of the first switch;
a second switch having a first terminal connected to the inverting input terminal of the amplifier;
a third switch having a first terminal connected to a second terminal of the second switch and a second terminal connected to the common voltage source;
a fourth switch having a first terminal connected to the inverting input terminal of the amplifier;
a first feedback capacitor having a first terminal connected to a second terminal of the fourth switch;
a fifth switch having a first terminal connected to a second terminal of the first feedback capacitor and a second terminal connected to an output terminal of the amplifier;
a sixth switch having a first terminal connected to the input voltage source and a second terminal connected to the second terminal of the first feedback capacitor;
a seventh switch having a first terminal connected to the second terminal of the fourth switch and a second terminal connected to the common voltage source;
an eighth switch having a first terminal connected to the inverting input terminal of the amplifier and a second terminal connected to the output terminal of the amplifier; and
a third voltage switch having a first terminal connected to a non-inverting input terminal of the amplifier, a second terminal connected to the common voltage source and a third terminal connected to the input voltage source.
1 Assignment
0 Petitions
Accused Products
Abstract
A touch panel sensing circuit senses a voltage variation of a coupling capacitor formed between a first directional signal line and a second directional signal line separated from the first directional signal line by a dielectric when an object approaches. The sensing circuit eliminates the parasitic capacitance effect on the signal lines and rapidly accumulates charges for an amplifier in sensing to thereby increase the operational speed of the sensing circuit.
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Citations
34 Claims
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1. A touch panel sensing circuit for sensing a voltage variation of a coupling capacitor formed between a first directional signal line and a second directional signal line separated from the first directional signal line when an object approaches, the touch panel sensing circuit comprising:
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an input voltage source for producing a plurality of periodic voltage cycles; a first voltage switch having a first terminal connected to the input voltage source and a second terminal connected to the first directional signal line; a common voltage source for providing a DC common voltage; a second voltage switch having a first terminal connected to the common voltage source and a second terminal connected to the first directional signal line; a first switch having a first terminal connected to the second directional signal line; an amplifier having an inverting input terminal connected to a second terminal of the first switch; a second switch having a first terminal connected to the inverting input terminal of the amplifier; a third switch having a first terminal connected to a second terminal of the second switch and a second terminal connected to the common voltage source; a fourth switch having a first terminal connected to the inverting input terminal of the amplifier; a first feedback capacitor having a first terminal connected to a second terminal of the fourth switch; a fifth switch having a first terminal connected to a second terminal of the first feedback capacitor and a second terminal connected to an output terminal of the amplifier; a sixth switch having a first terminal connected to the input voltage source and a second terminal connected to the second terminal of the first feedback capacitor; a seventh switch having a first terminal connected to the second terminal of the fourth switch and a second terminal connected to the common voltage source; an eighth switch having a first terminal connected to the inverting input terminal of the amplifier and a second terminal connected to the output terminal of the amplifier; and a third voltage switch having a first terminal connected to a non-inverting input terminal of the amplifier, a second terminal connected to the common voltage source and a third terminal connected to the input voltage source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A touch panel sensing circuit for sensing a voltage variation of a coupling capacitor formed between a first directional signal line and a second directional signal line separated from the first directional signal line when an object approaches, the touch panel sensing circuit comprising:
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an input voltage source for producing a plurality of periodic voltage cycles; a first voltage switch having a first terminal connected to the input voltage source and a second terminal connected to the first directional signal line; a common voltage source for providing a DC common voltage; a second voltage switch having a first terminal connected to the common voltage source and a second terminal connected to the first directional signal line; a first switch having a first terminal connected to the second directional signal line; an amplifier having an inverting input terminal connected to a second terminal of the first switch; a second switch having a first terminal connected to the inverting input terminal of the amplifier; a third switch having a first terminal connected to a second terminal of the second switch and a second terminal connected to the common voltage source; a fourth switch having a first terminal connected to the inverting input terminal of the amplifier; a first feedback capacitor having a first terminal connected to a second terminal of the fourth switch; a fifth switch having a first terminal connected to a second terminal of the first feedback capacitor and a second terminal connected to an output terminal of the amplifier; a sixth switch having a first terminal connected to the first directional signal line and a second terminal connected to the second terminal of the first feedback capacitor; a seventh switch having a first terminal connected to the second terminal of the fourth switch and a second terminal connected to the common voltage source; an eighth switch having a first terminal connected to the inverting input terminal of the amplifier and a second terminal connected to the output terminal of the amplifier; and a third voltage switch having a first terminal connected to a non-inverting input terminal of the amplifier, a second terminal connected to the common voltage source and a third terminal connected to the input voltage source. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A touch panel sensing circuit for sensing a voltage variation of a coupling capacitor formed between a first directional signal line and a second directional signal line separated from the first directional signal line when an object approaches, the touch panel sensing circuit comprising:
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an input voltage source for producing a plurality of periodic voltage cycles; a first voltage switch having a first terminal connected to the input voltage source and a second terminal connected to the first directional signal line; a common voltage source for providing a DC common voltage; a second voltage switch having a first terminal connected to the common voltage source and a second terminal connected to the first directional signal line; a first switch having a first terminal connected to the second directional signal line; an amplifier having an inverting input terminal connected to a second terminal of the first switch; a second switch having a first terminal connected to the inverting input terminal of the amplifier; a third switch having a first terminal connected to a second terminal of the second switch and a second terminal connected to the common voltage source; a fourth switch having a first terminal connected to the inverting input terminal of the amplifier; a first feedback capacitor having a first terminal connected to a second terminal of the fourth switch; a fifth switch having a first terminal connected to a second terminal of the first feedback capacitor and a second terminal connected to an output terminal of the amplifier; a seventh switch having a first terminal connected to the second terminal of the fourth switch and a second terminal connected to the common voltage source; an eighth switch having a first terminal connected to the inverting input terminal of the amplifier and a second terminal connected to the output terminal of the amplifier; and a third voltage switch having a first terminal connected to a non-inverting input terminal of the amplifier, a second terminal connected to the common voltage source and a third terminal connected to the input voltage source. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification