Touch panel with reduced charge time

A touch panel comprising:

• a sensing region having an equivalent capacitance at a predetermined location and including:
• a first end for receiving a pulse signal;
• a second end for providing a first signal before the touch panel receives a touch signal and for providing a second signal after the touch panel receives the touch signal;
• and
• a touch detection circuit comprising:
• a storage unit for providing a third signal by storing energy corresponding to the first signal, or for providing a fourth signal by storing energy corresponding to the second signal;
• and
• a precision rectifier circuit comprising:
• an input end coupled to the predetermined location;
• an output end coupled to the storage unit;
• and
• an operational amplifier including:
• an output end coupled to the output end of the precision rectifier circuit;
• a first input end coupled to the input end of the precision rectifier circuit;
• and
• a second input end coupled to the output end of the operational amplifier.

A method for determining where a touch signal occurs, comprising:

• providing a storage unit;
• providing a pulse signal for charging a sensing region at a predetermined location having an equivalent capacitance;
• providing a precision rectifier circuit for controlling a signal transmission path between the predetermined location and the storage unit, wherein the precision rectifier circuit includes an input end coupled to the predetermined location and an output end coupled to the storage unit;
• turning on the precision rectifier circuit for charging the storage unit when the precision rectifier circuit has a higher voltage level at the input end than at the output end during a charge period of the storage unit;
• and
• turning off the precision rectifier circuit when the precision rectifier circuit does not have a higher voltage level at the input end than at the output end during the charge period of the storage unit.