NOISE BLOCKING IN A CAPACITIVE TOUCH DEVICE
First Claim
1. A touch controller to be used by a touch screen device to provide a touch position, the touch controller comprising:
- a plurality of capacitance sensing channels that each provide an analog signal responsive to a touch on a screen;
a channel multiplexer to select at least one of the plurality of channels;
an analog-to-digital converter to change the analog signal of the selected capacitance sensing channel to a digital signal,a noise detecting channel coupled to a noise analog-to-digital converter to generate a noise digital signal;
a noise blocking timing generation block that combines a time shifted digital signal and a blocking signal, wherein the time shifted digital signal is formed by time shifting the digital signal and the blocking signal is related to the noise signal;
a capacitance calculating block coupled to the noise blocking time generation block to calculate capacitance values for each of the capacitance sensing channels; and
a position calculation unit to find the touch position on the screen based on the capacitance values for each of the capacitance sensing channels.
1 Assignment
0 Petitions
Accused Products
Abstract
A touch controller to be used by a touch screen device to provide a touch position is disclosed, including a plurality of capacitance sensing channels that each provide an analog signal responsive to a touch on a screen; a channel multiplexer to select at least one of the plurality of channels; an analog-to-digital converter to change the analog signal of the selected capacitance sensing channel to a digital signal; a noise detecting channel coupled to a noise analog-to-digital converter to generate a noise digital signal; a noise blocking timing generation block that combines a time shifted digital signal and a blocking signal, wherein the time shifted digital signal is formed by time shifting the digital signal and the blocking signal is related to the noise signal; a capacitance calculating block coupled to the noise blocking time generation block to calculate capacitance values for each of the capacitance sensing channels; and a position calculation unit to find the touch position on the screen based on the capacitance values for each of the capacitance sensing channels.
27 Citations
19 Claims
-
1. A touch controller to be used by a touch screen device to provide a touch position, the touch controller comprising:
-
a plurality of capacitance sensing channels that each provide an analog signal responsive to a touch on a screen; a channel multiplexer to select at least one of the plurality of channels; an analog-to-digital converter to change the analog signal of the selected capacitance sensing channel to a digital signal, a noise detecting channel coupled to a noise analog-to-digital converter to generate a noise digital signal; a noise blocking timing generation block that combines a time shifted digital signal and a blocking signal, wherein the time shifted digital signal is formed by time shifting the digital signal and the blocking signal is related to the noise signal; a capacitance calculating block coupled to the noise blocking time generation block to calculate capacitance values for each of the capacitance sensing channels; and a position calculation unit to find the touch position on the screen based on the capacitance values for each of the capacitance sensing channels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A touch screen device for finding a touch position on a screen and performing operations based on the touch position, further comprising:
-
a host processor, to perform operations based on the touch position; an LCD panel having a display image; a touch panel coupled to the LCD panel and coupled to a touch controller; an LCD noise antenna coupled to the touch panel and coupled to the touch controller; an LCD driver circuit coupled to the LCD panel to provide the display image;
whereinthe touch controller provides a touch position, the touch controller further comprising; a plurality of capacitance sensing channels that each provide an analog signal responsive to a touch on a screen; a channel multiplexer to select at least one of the plurality of channels; an analog-to-digital converter to change the analog signal of the selected capacitance sensing channel to a digital signal, a noise detecting channel coupled to a noise analog-to-digital converter to generate a noise digital signal; a noise blocking timing generation block that combines a time shifted digital signal and a blocking signal, wherein the time shifted digital signal is formed by time shifting the digital signal and the blocking signal is related to the noise signal; a capacitance calculating block coupled to the noise blocking time generation block to calculate capacitance values for each of the capacitance sensing channels; and a position calculation unit to find the touch position on the screen based on the capacitance values for each of the capacitance sensing channels. - View Dependent Claims (17)
-
-
18. A method for blocking noise in a touch screen device, the method comprising the steps of:
-
collecting an analog signal from at least one of a plurality of capacitance sensing channels; converting the analog signal into a digital signal; collecting a noise signal from a noise detecting channel; shifting the timing of the digital signal using a phase-shift block, and blocking a portion of the time shifted signal to avoid counting the noise signal; calculating the capacitance of each of the plurality of capacitance sensing channels; and finding the touch position from the capacitance calculated for each of the plurality of capacitance sensing channels. - View Dependent Claims (19)
-
Specification