Patent ID: 7643014

Claim:
A resistive touch screen measurement system comprising: a first switch having a first terminal coupled to a first voltage source; a second switch having one terminal coupled to a second voltage source; a first resistor coupled to the first switch and the second switch in a series connection; a comparator having a first input coupled to a second terminal of the first switch; a successive-approximation register having an input coupled to an output of the comparator; and a simulation circuit comprising: a second resistor; a third switch having a first terminal coupled to the first voltage source, and a second terminal coupled to the second resistor and a second input of the comparator; a fourth switch coupled to the second resistor and the second voltage source; a fifth switch set having a plurality of switches, each switch coupled to the second resistor and the first voltage source in a parallel connection with the third switch, and a control terminal of each switch of the fifth switch set coupled to an output of a set of outputs of the successive-approximation register; a sixth switch set having a plurality of switches, each switch coupled to the second resistor and the second voltage source in a parallel connection with the fourth switch, and a control terminal of each switch of the sixth switch set coupled to an output of the set of outputs of the successive-approximation register; and a set of inverters, each inverter coupled to a control terminal of a switch of the fifth switch set and an output of the outputs of the successive-approximation register.