PURPOSE: A touch sensor interface using a passive sigma delta modulator is provided to use the passive sigma delta modulator which is composed of switches, a capacitor for detection, and a comparator in order to read the touch of a touch panel, thereby reducing the size of a circuit. CONSTITUTION: A passive sigma delta modulator (10) is successively connected to panel capacitors installed in a touch panel and displays the number of pulse waves according to the touch of the touch panel. A counter and logic unit (20) counts the number of pulses during constant operating time through the pulse waves and displays different digital logic signals according to the number of pulses. On changing a connection from a panel capacitor to a next panel capacitor, a reset means discharges a panel capacitor and a capacitor for detection by connecting both ends of the panel capacitor and the capacitor for detection to the ground.
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