Patent ID: 7683892

Claim:
A touch sensing apparatus comprising: a flip-flop having a first input and a second input and an output; a sensor connected to the first input of the flip-flop and for receiving electricity signals from an object that touches the sensor; a microcontroller unit (MCU) having an input, a first output and a second output, the input for receiving and providing output signals of the flip-flop to the MCU to identify a touch on the sensor according to the output signals of the flip-flop, the first output for outputting a first AC signal to the first input of the flip-flop, and the second output for outputting a second AC signal to the second input of the flip-flop; an integration circuit interposed between the second input of the flip-flop and the second output of the MCU and for delaying the AC signal to be inputted to the second input of the flip-flop; and a resistor interposed between the first input of the flip-flop and the first output of the MCU; wherein: the flip-flop outputs a first type output signal at the output thereof when the sensor is not touched; the sensor receives electricity signals from the object, and causes a delay of the AC signal to be inputted to the first input of the flip-flop, the delay of the AC signal to be inputted to the first input of the flip-flop further causing the flip-flop to output a second type output signal at the output thereof; and the MCU detects an output change of the output signals of the flip-flop from the first type output signal to the second type output signal and accordingly identifies a touch on the sensor.