CAPACITIVE TOUCH SYSTEM USING DIFFERENTIAL SENSING AND OPERATING METHOD THEREOF
First Claim
1. A capacitive touch system comprising:
- a drive circuit configured to output a drive signal;
a capacitive sensing matrix comprising a plurality of sensing elements arranged in rows and columns;
an encoding module configured to encode the drive signal corresponding to each row of the sensing elements to output encoded drive signals;
a modulation module configured to modulate the encoded drive signals corresponding to each row of the sensing elements to concurrently output encoded and modulated drive signals to each row of the sensing elements;
a detection circuit coupled to the capacitive sensing matrix and configured to respectively generate a detection matrix according to a detection signal of each column of the sensing elements;
a decoding module configured to decode the detection matrices to output a two-dimensional detection vector corresponding to each of the sensing elements;
a first subtraction circuit configured to subtract a first digital component of the two-dimensional detection vector of a second sensing element among the plurality of sensing elements from a first digital component of the two-dimensional detection vector of a first sensing element among the plurality of sensing elements to generate a first component difference; and
a second subtraction circuit configured to subtract a second digital component of the two-dimensional detection vector of the second sensing element from a second digital component of the two-dimensional detection vector of the first sensing element to generate a second component difference.
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Abstract
A capacitive touch system including a drive end, a capacitive sensing matrix and a detection end is provided. The drive end concurrently inputs encoded and modulated drive signals into a plurality of channels of the capacitive sensing matrix within each drive time slot of a frame. The detection end detects a detection matrix of the channels in the frame and decodes the detection matrix to respectively generate a two-dimensional detection vector corresponding to each of the channels. The detection end further calculates a subtraction between components of the two-dimensional detection vectors associated with two receiving electrodes of the capacitive sensing matrix to eliminate interference from noises.
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Citations
20 Claims
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1. A capacitive touch system comprising:
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a drive circuit configured to output a drive signal; a capacitive sensing matrix comprising a plurality of sensing elements arranged in rows and columns; an encoding module configured to encode the drive signal corresponding to each row of the sensing elements to output encoded drive signals; a modulation module configured to modulate the encoded drive signals corresponding to each row of the sensing elements to concurrently output encoded and modulated drive signals to each row of the sensing elements; a detection circuit coupled to the capacitive sensing matrix and configured to respectively generate a detection matrix according to a detection signal of each column of the sensing elements; a decoding module configured to decode the detection matrices to output a two-dimensional detection vector corresponding to each of the sensing elements; a first subtraction circuit configured to subtract a first digital component of the two-dimensional detection vector of a second sensing element among the plurality of sensing elements from a first digital component of the two-dimensional detection vector of a first sensing element among the plurality of sensing elements to generate a first component difference; and a second subtraction circuit configured to subtract a second digital component of the two-dimensional detection vector of the second sensing element from a second digital component of the two-dimensional detection vector of the first sensing element to generate a second component difference. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An operating method of a capacitive touch system, the capacitive touch system comprising a capacitive sensing matrix which comprises a plurality of drive electrodes and a plurality of receiving electrodes, the operating method comprising:
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concurrently inputting encoded and modulated drive signals to the drive electrodes in each drive time slot of a plurality of drive time slots of a frame period of the capacitive sensing matrix; sequentially detecting the receiving electrodes of the capacitive sensing matrix within the frame period to respectively generate a detection matrix corresponding to each of the receiving electrodes; decoding the detection matrices to generate a plurality of two-dimensional detection vectors corresponding to each of the receiving electrodes, wherein each of the two-dimensional detection vectors includes a first digital component and a second digital component; sequentially performing a subtraction between first digital components of the two-dimensional detection vectors of two receiving electrodes among the plurality of receiving electrodes to generate first component differences; and sequentially performing a subtraction between second digital components of the two-dimensional detection vectors of two receiving electrodes among the plurality of receiving electrodes to generate second component differences. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A capacitive touch system comprising:
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a capacitive sensing matrix comprising a plurality of drive electrodes and a plurality of receiving electrodes; a drive end configured to concurrently input encoded and modulated drive signals to the drive electrodes in each drive time slot of a plurality of drive time slots of a frame period of the capacitive sensing matrix; a detection circuit configured to sequentially couple to a first receiving electrode and a second receiving electrode among the plurality of receiving electrodes within the frame period, generate a first detection matrix corresponding to the first receiving electrode and generate a second detection matrix corresponding to the second receiving electrode; at least one decoding module configured to decode the first decoding matrix and the second decoding matrix to generate a plurality of first detection vectors corresponding to the first receiving electrode and generate a plurality of second detection vectors corresponding to the second receiving electrode; a first subtraction circuit configured to perform a subtraction between first digital components of the first detection vectors and the second detection vectors to generate a first component difference; and a second subtraction circuit configured to perform a subtraction between second digital components of the first detection vectors and the second detection vectors to generate a second component difference. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification