CAPACITIVE DISCHARGE CIRCUIT FOR TOUCH SENSITIVE SCREEN
First Claim
1. A capacitive discharge circuit comprising:
- a line having a capacitance associated therewith;
a switched capacitor circuit comprising a capacitor;
a switched circuit coupled to the line;
a voltage regulator circuit coupled between the switched capacitor circuit and the switched circuit; and
a controller configured to operate the switched capacitor circuit and the switched circuit so as to;
in a first phase, charge the capacitor by coupling the capacitor between a common mode node and a power supply node,in a second phase, discharge the capacitor by coupling the voltage regulator circuit in series with the capacitor between the power supply node and a ground node,in a third phase, charge the capacitor by coupling the capacitor between the common mode node and the power supply node, andin a fourth phase, share charge between the line and the capacitor by coupling the voltage regulator circuit and the capacitor in series between the line and the ground node.
1 Assignment
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Accused Products
Abstract
A capacitive discharge circuit includes a line having a capacitance, a switched capacitor circuit including a capacitor, a switched circuit coupled to the line, and a voltage regulator coupled between the switched capacitor circuit and the switched circuit. A controller operates the switched capacitor circuit and switched circuit to in a first phase, charge the capacitor by coupling the capacitor between a common mode and a power supply, and in a second phase, discharge the capacitor by coupling the voltage regulator in series with the capacitor between the power supply node a ground. The controller is also configured to in a third phase, charge the capacitor by coupling the capacitor between the common mode and the power supply, and in a fourth phase, share charge between the line and the capacitor by coupling the voltage regulator and the capacitor in series between the line and the ground.
8 Citations
22 Claims
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1. A capacitive discharge circuit comprising:
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a line having a capacitance associated therewith; a switched capacitor circuit comprising a capacitor; a switched circuit coupled to the line; a voltage regulator circuit coupled between the switched capacitor circuit and the switched circuit; and a controller configured to operate the switched capacitor circuit and the switched circuit so as to; in a first phase, charge the capacitor by coupling the capacitor between a common mode node and a power supply node, in a second phase, discharge the capacitor by coupling the voltage regulator circuit in series with the capacitor between the power supply node and a ground node, in a third phase, charge the capacitor by coupling the capacitor between the common mode node and the power supply node, and in a fourth phase, share charge between the line and the capacitor by coupling the voltage regulator circuit and the capacitor in series between the line and the ground node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An electronic device comprising:
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a touch sensitive display; an input line coupled to the touch sensitive display; a voltage regulator circuit; a capacitor having first and second terminals; a first switch circuit having inputs coupled to the voltage regulator circuit and to a common mode node, and an output coupled to the first terminal of the capacitor; a second switch circuit having inputs coupled to a power supply node and to a ground node, and an output coupled to the second terminal of the capacitor; and a third switch circuit having inputs coupled to the input line and to the power supply node, and an output coupled to the voltage regulator circuit. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of discharging a capacitance on a line comprising:
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in a first phase, charge a capacitor by coupling the capacitor between a common mode node and a power supply node, in a second phase, discharge the capacitor by coupling a voltage regulator circuit in series with the capacitor between the power supply node and a ground node, in a third phase, charge the capacitor by coupling the capacitor between the common mode node and the power supply node, and in a fourth phase, share charge between the line and the capacitor by coupling the voltage regulator circuit and capacitor in series between the line and the ground node. - View Dependent Claims (19, 20, 21, 22)
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Specification