Patent ID: 8638110

Claim:
A high resolution circuit for converting a capacitance difference between a first and second capacitance into a phase difference between two pulse signals, the circuit comprising: a capacitance deviation detecting unit configured to generate first and second detection pulse signals having first and second frequencies corresponding to the first and second capacitances of a capacitive sensor, respectively; a capacitance deviation amplifying unit configured to divide the frequencies of the first and second detection pulse signals to amplify a phase difference between the first and second detection pulse signals; and a time signal generating unit configured to generate a time signal having a pulse width corresponding to the amplified phase difference, wherein the capacitance deviation detecting unit comprises first and second capacitance detecting units configured to generate the first and second detection pulse signals, respectively, and wherein the first capacitance detecting unit comprises: a first comparator configured to output the first detection pulse signal having a first logical value when a first input node charged and discharged according to the first capacitance has a voltage level equal to or less than that of a first reference voltage, and otherwise to output the first detection pulse signal having a second logical value; a first charging switch configured to apply a charging current to the first input node when the first detection pulse signal has the first logical value; and a first discharging switch configured to discharge the first input node charged according to the first capacitance when the first detection pulse signal has the second logical value.