Panel bootstraping architectures for in-cell self-capacitance
A self-capacitance touch screen. In some examples, the touch screen comprises a plurality of display pixels, a first display pixel of the plurality of display pixels including a first touch electrode of a plurality of touch electrodes, and a gate line coupled to the first display pixel, wherein the gate line is configured such that a voltage at the gate line substantially follows a voltage at the first touch electrode. In some examples, the gate line is coupled to a resistor, the resistor being configured to decouple the gate line from ground. In some examples, the gate line is coupled to an AC voltage source.
1. A self-capacitance touch screen, the touch screen comprising:
a plurality of display pixels, a first display pixel of the plurality of display pixels including a first touch electrode of a plurality of touch electrodes; and
a gate line coupled to the first display pixel, wherein the gate line is coupled to a resistor that:
decouples the gate line from ground with respect to one or more AC signals such that a voltage difference between the gate line and the first touch electrode remains substantially unchanged while a self-capacitance of the first touch electrode is being sensed, which includes driving the first touch electrode at an AC voltage; and
allows one or more DC signals for operating the first display pixel to pass onto the gate line during a touch mode of the touch screen.
2. The touch screen of claim 1 , wherein the touch screen is configured to enable an AC voltage to be present at both the gate line and the first touch electrode.
3. The touch screen of claim 1 , wherein the resistor is in a border region of the touch screen.
4. The touch screen of claim 1 , wherein the resistor is coupled to an AC voltage source.
5. The touch screen of claim 4 , wherein:
the AC voltage source is coupled to sense circuitry, and
the sense circuitry is coupled to the first touch electrode.
6. The touch screen of claim 1 , wherein the gate line is coupled to an AC voltage source.
7. The touch screen of claim 6 , further comprising sense circuitry coupled to: the first touch electrode, and the AC voltage source.
8. The touch screen of claim 6 , wherein the gate line is further coupled to a DC voltage source.
9. The touch screen of claim 1 , wherein the gate line is coupled to a transistor in the first display pixel.
10. The touch screen of claim 1 , wherein the gate line is further coupled to a second display pixel of the plurality of display pixels.
11. A method for operating a self-capacitance touch screen, the method comprising:
coupling a gate line to:
a first display pixel of a plurality of display pixels, the first display pixel including a first touch electrode of a plurality of touch electrodes; and
a resistor that:
decouples the gate line from ground with respect to one or more AC signals;
allows one or more DC signals for operating the first display pixel to pass onto the gate line during a touch mode of the touch screen; and
operating the gate line such that a voltage difference between the gate line and the first touch electrode remains substantially unchanged while a self-capacitance of the first touch electrode is being sensed, which includes driving the first touch electrode at an AC voltage.
12. The method of claim 11 , wherein the voltage at the gate line and the voltage at the first touch electrode comprise an AC voltage.
13. The method of claim 11 , wherein the resistor is in a border region of the touch screen.
14. The method of claim 11 , further comprising coupling the resistor to an AC voltage source.
15. The method of claim 14 , further comprising:
coupling the AC voltage source to sense circuitry; and
coupling the sense circuitry to the first touch electrode.
16. The method of claim 11 , wherein operating the gate line comprises coupling the gate line to an AC voltage source.
17. The method of claim 16 , further comprising coupling the first touch electrode and the AC voltage source to sense circuitry.
18. The method of claim 16 , further comprising coupling the gate line to a DC voltage source.
19. The method of claim 11 , wherein coupling the gate line to the first display pixel comprises coupling the gate line to a transistor in the first display pixel.
20. The method of claim 11 , further comprising coupling the gate line to a second display pixel of the plurality of display pixels.