Touch screen sensor controller with drive sense circuits
A touch screen display includes a display, a video graphics processing module, electrodes integrated into at least a portion of the display, and drive-sense circuits coupled to the electrodes. The drive-sense circuits, when enabled and concurrent with the display rendering frames of data into the visible images, detect changes in electrical characteristics of electrodes. At least some drive-sense circuits monitor sensor signals on at least some electrodes. A sensor signal includes a drive signal component and a receive signal component. The at least some drive-sense circuits generate the drive signal components of the sensor signals. The receive signal component is a representation of a change in an electrical characteristic of an electrode of the at least some electrodes when a corresponding drive signal component is applied to the electrode. The change in the electrical characteristic of the electrode is indicative of a proximal touch to the touch screen display.
1. A touch screen sensor controller comprises:
a plurality of row drive sense circuits for coupling to a plurality of row electrodes of a touch screen, wherein a row electrode of the plurality of row electrodes has a self-capacitance with respect to a ground reference of the touch sense circuit;
a plurality of column drive sense circuits for coupling to a plurality of column electrodes of the touch screen, wherein a column electrode of the plurality of column electrodes has a self-capacitance to the ground reference, and wherein a mutual capacitance is between the row electrode and the column electrode;
a processing module operably coupled to the plurality of row drive sense circuit and to the plurality of column drive sense circuits, wherein the processing module is operable to, when the plurality of row drive sense circuits is coupled to the plurality of row electrodes and the plurality of column drive sense circuits is coupled to the plurality of column electrodes:
substantially concurrently enable a set of row drive sense circuits of the plurality of row drive sense circuits and a set of column drive sense circuits of the plurality of drive sense circuits, wherein the set of row drive sense circuits detects self-capacitances of a set of row electrodes coupled to the set of row drive sense circuits, wherein the set of column drive sense circuits detects self-capacitances of a set of column electrodes coupled to the set of column drive sense circuits, and wherein the set of row drive sense circuits or the set of column drive sense circuits detects the mutual capacitances of the set of row electrodes and the set of column electrodes; and
generate, during a first time interval, a first capacitive image frame based on the self-capacitances of the set of row electrodes, the self-capacitances of the set of column electrodes, and the mutual capacitances of the set of row electrodes and the set of column electrodes;
generate, during a second-time interval, a second capacitive image as a second capacitive image frame; and
generate, during a third-time interval, a third capacitive image as a third capacitive image frame.
2. The touch screen sensor controller of claim 1 , wherein the processing module is further operable to:
generate a capacitance video based on the first, second, and third capacitive image frames.
3. The touch screen sensor controller of claim 1 further comprises:
the row drive sense circuit including:
a first-row conversion circuit operable to convert a receive row signal component into a sensed row signal representative of a capacitance; and
a second-row conversion circuit operable to convert the sensed row signal into a drive row signal component;
the column drive sense circuit including:
a first column conversion circuit operable to convert a receive column signal component into a sensed column signal representative of a capacitance; and
a second column conversion circuit operable to convert the sensed column signal into a drive column signal component.
4. The touch screen sensor controller of claim 1 , wherein the processing module is further operable to substantially concurrently enable the set of row drive sense circuits and the set of column drive sense circuits by:
enabling a common self-capacitance reference signal to be provided to the set of row drive sense circuits and to the set of column sense circuits; and
enabling a set of mutual capacitance reference signals to be provided to one of the set of row drive sense circuits and to the set of column sense circuits, wherein the other one of the set of row drive sense circuits and to the set of column sense circuits senses the mutual capacitances of the of the set of row electrodes and the set of column electrodes, and wherein an oscillating component of the common self-capacitance reference signal is at a different frequency than the oscillating components of the set of mutual capacitance reference signals.
5. The touch screen sensor controller of claim 1 further comprises:
the set of row drive sense circuits including two or more row drive sense circuits of the plurality of row drive sense circuits; and
the set of column drive sense circuits including two or more column drive sense circuits of the plurality of column drive sense circuits.
6. The touch screen sensor controller of claim 1 , wherein the processing module is further operable to:
interpret the capacitive image to identify no touch, an undesired touch, and/or a desired touch.
7. The touch screen sensor controller of claim 1 , wherein the processing module is further operable to:
substantially concurrently enable a second set of row drive sense circuits of the plurality of row drive sense circuits and a second set of column drive sense circuits of the plurality of drive sense circuits, wherein the second set of row drive sense circuits detects self-capacitances of a second set of row electrodes coupled to the second set of row drive sense circuits, wherein the second set of column drive sense circuits detects self-capacitances of a second set of column electrodes coupled to the second set of column drive sense circuits, and wherein the second set of row drive sense circuits or the second set of column drive sense circuits detects the mutual capacitances of the second set of row electrodes and the second set of column electrodes; and
generate a second capacitive image based on the self-capacitances of the second set of row electrodes, the self-capacitances of the second set of column electrodes, and the mutual capacitances of the second set of row electrodes and the second set of column electrodes.
8. The touch screen sensor controller of claim 7 , wherein the processing module is further operable to:
combine the capacitive image and the second capacitive image to produce a frame of a capacitive image.
9. A touch screen comprises:
a plurality of row electrodes, wherein a row electrode of the plurality of row electrodes has a self-capacitance with respect to a ground reference of the touch screen;
a plurality of column electrodes, wherein a column electrode of the plurality of column electrodes has a self-capacitance to the ground reference, and wherein a mutual capacitance is between the row electrode and the column electrode;
a plurality of row drive sense circuits for coupling to the plurality of row electrodes;
a plurality of column drive sense circuits for coupling to a plurality of column electrodes of the touch screen circuit;
a processing module operably coupled to the plurality of row drive sense circuit and to the plurality of column drive sense circuits, wherein the processing module is operable to, when the plurality of row drive sense circuits is coupled to the plurality of row electrodes and the plurality of column drive sense circuits is coupled to the plurality of column electrodes:
substantially concurrently enable a set of row drive sense circuits of the plurality of row drive sense circuits and a set of column drive sense circuits of the plurality of drive sense circuits, wherein the set of row drive sense circuits detects self-capacitances of a set of row electrodes coupled to the set of row drive sense circuits, wherein the set of column drive sense circuits detects self-capacitances of a set of column electrodes coupled to the set of column drive sense circuits, and wherein the set of row drive sense circuits or the set of column drive sense circuits detects the mutual capacitances of the set of row electrodes and the set of column electrodes; and
generate, during a first time interval, a first capacitive image frame based on the self-capacitances of the set of row electrodes, the self-capacitances of the set of column electrodes, and the mutual capacitances of the set of row electrodes and the set of column electrodes;
generate, during a second-time interval, a second capacitive image as a second capacitive image frame; and
generate, during a third-time interval, a third capacitive image as a third capacitive image frame.
10. The touch screen of claim 9 , wherein the processing module is further operable to:
generate a capacitance video based on the first, second, and third capacitive image frames.
11. The touch screen of claim 9 further comprises:
the row drive sense circuit including:
a first-row conversion circuit operable to convert a receive row signal component into a sensed row signal representative of a capacitance; and
a second-row conversion circuit operable to convert the sensed row signal into a drive row signal component;
the column drive sense circuit including:
a first column conversion circuit operable to convert a receive column signal component into a sensed column signal representative of a capacitance; and
a second column conversion circuit operable to convert the sensed column signal into a drive column signal component.
12. The touch screen of claim 9 , wherein the processing module is further operable to substantially concurrently enable the set of row drive sense circuits and the set of column drive sense circuits by:
enabling a common self-capacitance reference signal to be provided to the set of row drive sense circuits and to the set of column sense circuits; and
enabling a set of mutual capacitance reference signals to be provided to one of the set of row drive sense circuits and to the set of column sense circuits, wherein the other one of the set of row drive sense circuits and to the set of column sense circuits senses the mutual capacitances of the of the set of row electrodes and the set of column electrodes, and wherein an oscillating component of the common self-capacitance reference signal is at a different frequency than the oscillating components of the set of mutual capacitance reference signals.
13. The touch screen of claim 9 further comprises:
the set of row drive sense circuits including two or more row drive sense circuits of the plurality of row drive sense circuits; and
the set of column drive sense circuits including two or more column drive sense circuits of the plurality of column drive sense circuits.
14. The touch screen of claim 9 , wherein the processing module is further operable to:
interpret the capacitive image to identify no touch, an undesired touch, and/or a desired touch.
15. The touch screen of claim 9 , wherein the processing module is further operable to:
substantially concurrently enable a second set of row drive sense circuits of the plurality of row drive sense circuits and a second set of column drive sense circuits of the plurality of drive sense circuits, wherein the second set of row drive sense circuits detects self-capacitances of a second set of row electrodes coupled to the second set of row drive sense circuits, wherein the second set of column drive sense circuits detects self-capacitances of a second set of column electrodes coupled to the second set of column drive sense circuits, and wherein the second set of row drive sense circuits or the second set of column drive sense circuits detects the mutual capacitances of the second set of row electrodes and the second set of column electrodes; and
generate a second capacitive image based on the self-capacitances of the second set of row electrodes, the self-capacitances of the second set of column electrodes, and the mutual capacitances of the second set of row electrodes and the second set of column electrodes.
16. The touch screen of claim 15 , wherein the processing module is further operable to:
combine the capacitive image and the second capacitive image to produce a frame of a capacitive image.
17. A non-transitory computer readable storage device comprises:
a first memory section that stores operational instructions that, when executed by a processing module of a touch screen sensor controller, causes the processing module to, when a plurality of row drive sense circuits is coupled to a plurality of row electrodes of a touch screen and a plurality of column drive sense circuits is coupled to a plurality of column electrodes of the touch screen:
substantially concurrently enable a set of row drive sense circuits of the plurality of row drive sense circuits and a set of column drive sense circuits of the plurality of drive sense circuits, wherein the set of row drive sense circuits detects self-capacitances of a set of row electrodes coupled to the set of row drive sense circuits, wherein the set of column drive sense circuits detects self-capacitances of a set of column electrodes coupled to the set of column drive sense circuits, and wherein the set of row drive sense circuits or the set of column drive sense circuits detects the mutual capacitances of the set of row electrodes and the set of column electrodes; and
a second memory section that stores operational instructions that, when executed by the processing module, causes the processing module to:
generate, during a first time interval, a first capacitive image frame based on the self-capacitances of the set of row electrodes, the self-capacitances of the set of column electrodes, and the mutual capacitances of the set of row electrodes and the set of column electrodes;
generate, during a second-time interval, a second capacitive image as a second capacitive image frame; and
generate, during a third-time interval, a third capacitive image as a third capacitive image frame.
18. The non-transitory computer readable storage device of claim 17 , wherein the second memory section further stores operational instructions that, when executed by the processing module, causes the processing module to:
generate a capacitance video based on the first, second, and third capacitive image frames.
19. The non-transitory computer readable storage device of claim 17 , wherein the first memory section further stores operational instructions that, when executed by the processing module, causes the processing module to substantially concurrently enable the set of row drive sense circuits and the set of column drive sense circuits by:
enabling a common self-capacitance reference signal to be provided to the set of row drive sense circuits and to the set of column sense circuits; and
enabling a set of mutual capacitance reference signals to be provided to one of the set of row drive sense circuits and to the set of column sense circuits, wherein the other one of the set of row drive sense circuits and to the set of column sense circuits senses the mutual capacitances of the of the set of row electrodes and the set of column electrodes, and wherein an oscillating component of the common self-capacitance reference signal is at a different frequency than the oscillating components of the set of mutual capacitance reference signals.
20. The non-transitory computer readable storage device of claim 17 , wherein the second memory section further stores operational instructions that, when executed by the processing module, causes the processing module to:
interpret the capacitive image to identify no touch, an undesired touch, and/or a desired touch.
21. The non-transitory computer readable storage device of claim 17 further comprises:
the first memory section further stores operational instructions that, when executed by the processing module, causes the processing module to:
substantially concurrently enable a second set of row drive sense circuits of the plurality of row drive sense circuits and a second set of column drive sense circuits of the plurality of drive sense circuits, wherein the second set of row drive sense circuits detects self-capacitances of a second set of row electrodes coupled to the second set of row drive sense circuits, wherein the second set of column drive sense circuits detects self-capacitances of a second set of column electrodes coupled to the second set of column drive sense circuits, and wherein the second set of row drive sense circuits or the second set of column drive sense circuits detects the mutual capacitances of the second set of row electrodes and the second set of column electrodes; and
the second memory section further stores operational instructions that, when executed by the processing module, causes the processing module to:
generate a second capacitive image based on the self-capacitances of the second set of row electrodes, the self-capacitances of the second set of column electrodes, and the mutual capacitances of the second set of row electrodes and the second set of column electrodes.
22. The non-transitory computer readable storage device of claim 21 , wherein the second memory section further stores operational instructions that, when executed by the processing module, causes the processing module to:
combine the capacitive image and the second capacitive image to produce a frame of a capacitive image.