Touch sensing circuit and method, touch screen and display device

A touch sensing method applied in a touch sensing circuit comprising:

• a touch sensing unit, an output control unit and a detection unit;
• the touch sensing unit is connected with a first control line, a first power source, a second power source and the output control unit, for providing a touch current, and the touch current is transmitted to the output control unit;
• the output control unit is connected with a second control line, a read-out line, the touch sensing unit and the detection unit, for outputting the touch current to the detection unit through the read-out line;
• the detection unit is connected with a reference voltage terminal, an output terminal, the read-out line and the output control unit, for detecting significant change in a voltage output by the output control unit, thereby determining a location where a touch occurs, wherein
• the touch sensing unit comprises:
• a first transistor, a second transistor, a touch electrode, a first capacitor, and a second capacitor;
• a second electrode of the first transistor is connected to a first terminal of the first capacitor;
• a control electrode of the second transistor is connected to the touch electrode, a first electrode of the second transistor is connected to the first power source, and a second electrode of the second transistor is connected to the output control unit;
• a second terminal of the first capacitor is connected to the touch electrode;
• and
• a first terminal of the second capacitor is connected to the touch electrode, and a second terminal of the second capacitor is connected to the second power source,
• the touch sensing method comprising steps of:
• providing touch current by the touch sensing unit under control of a first control line, a first power source and a second power source, and transmitting the touch current to the output control unit;
• outputting the touch current to the detection unit through the read-out line, by the output control unit under control of a second control line;
• under control of the reference voltage terminal, detecting significant change in the voltage output from the output control unit by the detection unit through the read-out line, thereby determining the location where the touch occurs.