Control unit for contact position sensor for resistive touch screen in computer, has differential output coupled with capacitors, which provides measure of voltage difference between capacitors to portion of downstream circuitry

摘要

The control unit (150) has a timing circuit which is coupled with switches. A main capacitor coupled to main switch is more operable to receive the charge amount, and to indicate capacitance of region (104) of the capacitive touch sensor (105). An auxiliary capacitor is coupled to auxiliary switch, so as to discharge the charge amount and indicate the capacitance of the region of touch sensor. A differential output is coupled with the capacitors, in order to provide measure of the voltage difference between the capacitors to a portion of downstream circuitry.