Electronic device for detecting proximity of user and operation method thereof

An electronic device for detecting proximity of a user comprising:

• an antenna, wherein a voltage of the antenna is a voltage of a reference capacitor serving as an equivalent circuit for the antenna, the reference capacitor having a capacitance corresponding to at least one capacitor connected to the antenna;
• a variable element configured to have a capacitance in a designated range, wherein an upper limit of the designated range is smaller than the capacitance of the reference capacitor;
• and
• an amplifier connected to the variable element and configured to amplify a voltage of the variable element to a voltage of the reference capacitor and output the amplified voltage,
• wherein the capacitance of the reference capacitor corresponds to a first change rate of the voltage of the reference capacitor during a designated time interval.

An operation method of an electronic device configured to detect whether a user is close, the operation method comprising:

• identifying a change rate during a predetermined time interval of an output voltage of an amplifier configured to amplify, by a designated ratio, a voltage of a variable element configured to have a capacitance in a designated range;
• identifying a change rate during the predetermined time interval of a voltage of a reference capacitor serving as an equivalent circuit for an antenna;
• determining whether the identified change rate of the output voltage of the amplifier during the predetermined time interval is greater than the change rate of the voltage of the reference capacitor during the predetermined time interval;
• and
• changing the designated ratio of the amplifier in response to determining that the identified change rate of the output voltage of the amplifier during the predetermined time interval is greater than the change rate of the voltage of the reference capacitor during the predetermined time interval.