Disclosed herein is a device including a differential amplification unit
for supplying current to the touch panel; a signal amplification unit for
amplifying the output voltage of the differential amplification unit; an
analog-digital conversion unit for converting the analog output signal of
the signal amplification unit into a digital signal; a control unit for
measuring the signal output from the analog-digital conversion unit and
detecting the position of an object when the object touches the touch
panel; and a sine wave generating unit for providing a sine wave signal
to the differential amplification unit in response to the output signal
of the control unit, supplying a maximum current to the differential
amplification unit while the touch panel is in a standby state, and
controlling the level of the sine wave signal in response to conductivity
of the object when the object touches the touch panel.