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.
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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.
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Citations
14 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. 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 (11, 12, 13, 14)
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Specification