Touch apparatus and sensing method and touch sensing circuit thereof

1. A touch apparatus, comprising:

a touch panel, having a plurality of sensing electrodes to sense a touch event; and

a touch sensing circuit, coupled to the touch panel to read sensing information of the sensing electrodes, comprising:

an analog front end circuit;

a switch circuit, directly connected to an input end of the analog front end circuit, and coupled to a plurality of same-column electrodes of the sensing electrodes in the same column,

wherein:

in a first period, the switch circuit couples the same-column electrodes to the input end of the analog front end circuit by turns such that the analog front end circuit performs self-capacitance touch detection on the same-column electrodes in a time division manner, the touch sensing circuit applies a same driving signal to the sensing electrodes at the same time, and the touch sensing circuit performs the self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result, and

in a second period, the touch sensing circuit performs the mutual-capacitance touch detection on one target sensing electrode of the same-column electrodes to obtain a mutual-capacitance detection result, wherein in the mutual-capacitance touch detection, only the target sensing electrode is coupled to the analog front end circuit of the touch sensing circuit, and a driving signal is applied to the rest of the same-column electrodes, and

the touch sensing circuit determines whether the touch event is triggered by water based on the mutual-capacitance detection result and the self-capacitance detection result,

wherein the touch sensing circuit determining whether the touch event is triggered by the water further comprises:

having determined that the touch event is triggered by the water, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes and performs the self-capacitance touch detection on the sensing electrodes to obtain a location of the water.

2. The touch apparatus as claimed in claim 1 , wherein the touch panel is an in-cell touch display panel, and the sensing electrodes are a plurality of common electrodes in the in-cell touch display panel.

3. The touch apparatus as claimed in claim 1 , wherein the touch sensing circuit determines that the touch event is triggered by the water when the mutual-capacitance detection result indicates that the touch event occurs on the touch panel, but the self-capacitance detection result indicates that the touch event does not occur on the touch panel.

4. The touch apparatus as claimed in claim 3 , wherein the touch sensing circuit reports the location of the water to a processor.

5. The touch apparatus as claimed in claim 1 , wherein the analog front end circuit comprises:

an operational amplifier, having an inverting input end, a non-inverting input end and an output end, wherein the inverting input end is coupled to the switch circuit, and the non-inverting input end is coupled to a reference voltage; and

a capacitor, having a first end and a second end respectively coupled to the inverting input end and the output end of the operational amplifier.

6. The touch apparatus as claimed in claim 5 , wherein the reference voltage is a clock signal in the first period, and the reference voltage is a fixed voltage in the second period.

7. A sensing method of a touch apparatus, comprising:

providing a touch panel to sense a touch event;

coupling a plurality of same-column electrodes to an input end of an analog front end circuit by turns by a switch circuit that is directly connected to the analog front end circuit such that the analog front end circuit performs self-capacitance touch detection on the same-column electrodes in a time division manner, and applying a same driving signal to a plurality of sensing electrodes of the touch panel at the same time by a touch sensing circuit and performing the self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result in a first period;

performing the mutual-capacitance touch detection on one target sensing electrode of the same-column electrodes by the touch sensing circuit to obtain a mutual-capacitance detection result in a second period, wherein in the mutual-capacitance touch detection, only the target sensing electrode is coupled to the analog front end circuit of the touch sensing circuit, and a driving signal is applied to the rest of the same-column electrodes;

determining whether the touch event is triggered by water by the touch sensing circuit based on the mutual-capacitance detection result and the self-capacitance detection result; and

when determining that the touch event is triggered by the water, applying the same driving signal to the sensing electrodes, and performing the self-capacitance touch detection on the sensing electrodes to obtain a location of the water by the touch sensing circuit.

8. The sensing method as claimed in claim 7 , wherein the touch panel is an in-cell touch display panel, and the sensing electrodes are a plurality of common electrodes in the in-cell touch display panel.

9. The sensing method as claimed in claim 7 , wherein the touch sensing circuit determines that the touch event is triggered by the water when the mutual-capacitance detection result indicates that the touch event occurs on the touch panel, but the self-capacitance detection result indicates that the touch event does not occur on the touch panel.

10. The sensing method as claimed in claim 9 , further comprising:

reporting the location of the water to a processor.

11. A touch sensing circuit for reading sensing information of a plurality of sensing electrodes of a touch panel, comprising:

an analog front end circuit; and

a switch circuit, directly connected to an input end of the analog front end circuit, and coupled to a plurality of same-column electrodes of the sensing electrodes in the same column,

wherein:

in a first period, the switch circuit couples the same-column electrodes to the input end of the analog front end circuit by turns such that the analog front end circuit performs self-capacitance touch detection on the same-column electrodes in a time division manner, the touch sensing circuit applies a same driving signal to the sensing electrodes at the same time and performs the self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result,

in a second period, the touch sensing circuit performs the mutual-capacitance touch detection on one target sensing electrode of the same-column electrodes to obtain a mutual-capacitance detection result, wherein in the mutual-capacitance touch detection, only the target sensing electrode is coupled to the analog front end circuit of the touch sensing circuit, and a driving signal is applied to the rest of the same-column electrodes, and

the touch sensing circuit determines whether a touch event of the touch panel is triggered by water based on the mutual-capacitance detection result and the self-capacitance detection result, and

wherein the touch sensing circuit determining whether the touch event is triggered by the water further comprises:

having determined that the touch event is triggered by the water, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes and performs the self-capacitance touch detection on the sensing electrodes to obtain a location of the water.

12. The touch sensing circuit as claimed in claim 11 , wherein the touch sensing circuit determines that the touch event is triggered by the water when the mutual-capacitance detection result indicates that the touch event occurs on the touch panel, but the self-capacitance detection result indicates that the touch event does not occur on the touch panel.

13. The touch sensing circuit as claimed in claim 12 , wherein the touching sensing circuit reports the location of the water to a processor.

14. The touch sensing circuit as claimed in claim 11 , wherein the analog front end circuit comprises:

an operational amplifier, having an inverting input end, a non-inverting input end and an output end, wherein the inverting input end is coupled to the switch circuit, and the non-inverting input end is coupled to a reference voltage; and

a capacitor, having a first end and a second end respectively coupled to the inverting input end and the output end of the operational amplifier.

15. The touch sensing circuit as claimed in claim 14 , wherein the reference voltage is a clock signal in the first period, and the reference voltage is a fixed voltage in the second period.