CAPACITANCE MEASURING CIRCUIT FOR TOUCH SENSOR

摘要

A capacitance measuring circuit for a touch sensor is provided to measure capacitance and variation of an electrode by measuring time required for charging/ discharging of capacitance. A reference voltage generation unit(10) generates a first reference voltage and a second reference voltage. A mux unit(60) selects one electrode from a plurality of electrodes(70), and a comparison unit(20) compares a voltage from the electrode and with a voltage generated from a reference voltage unit. A charge / discharge circuit part(50) charges the electrode from a first reference voltage electrode to a second reference voltage. A timer(40) measures charge and discharge time of the charge / discharge circuit part.