DIFFERENTIAL SENSING FOR CAPACITIVE TOUCH SENSORS
First Claim
Patent Images
1. A touch sensor operable to sense a differential measurement between two sense lines, comprising:
- a summing circuit connected to a touch sensor controller;
a first buffer that includes a first input connected to a first sense line of the touch sensor and a first output connected to the summing circuit;
a second buffer that includes a second input connected to a second sense line of the touch sensor and a second output connected to the first summing circuit; and
wherein the summing circuit is operable to;
receive a first capacitive measurement of the first sense line from the first buffer;
receive a second capacitive measurement of the second sense line from the second buffer; and
output a difference between the first capacitive measurement and the second capacitive measurement to the touch sensor controller.
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Abstract
A first signal from a first sense line of a touch sensor is received. A second signal from a second of the touch sensor is received. The first signal is inverted. The inverted first signal and the second signal are summed to produce a differential signal. The differential signal is output to a touch sensor controller.
23 Citations
20 Claims
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1. A touch sensor operable to sense a differential measurement between two sense lines, comprising:
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a summing circuit connected to a touch sensor controller; a first buffer that includes a first input connected to a first sense line of the touch sensor and a first output connected to the summing circuit; a second buffer that includes a second input connected to a second sense line of the touch sensor and a second output connected to the first summing circuit; and wherein the summing circuit is operable to; receive a first capacitive measurement of the first sense line from the first buffer; receive a second capacitive measurement of the second sense line from the second buffer; and output a difference between the first capacitive measurement and the second capacitive measurement to the touch sensor controller. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method, comprising:
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receiving a first signal from a first sense line of a touch sensor; receiving a second signal from a second sense line of the touch sensor; inverting the first signal; summing the inverted first signal and the second signal to produce a differential signal; and outputting the differential signal to a touch sensor controller. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A system comprising:
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a touch sensor, operable to measure a differential signal that represents a difference between a first measurement of a first sense line and a second measurement of a second sense line; and a touch sensor controller coupled to the touch sensor and operable to; receive the differential signal from the touch sensor; and determine a location of a touch object based on the differential signal. - View Dependent Claims (17, 18, 19, 20)
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Specification