Abstract: An apparatus and method are provided to rapidly and accurately measure the variation of capacitance in a panel load of a touch sensor and thus increase touch sensitivity and noise resistance. The apparatus includes a panel driver configured to drive a panel load in the touch sensor according to a reference voltage, and a capacitive load detector configured to measure capacitance of the panel load by sensing a panel load driving current that is applied to the panel load by the panel driver.

Abstract: A stepdown DC-DC converter is adapted to provide a power supply voltage necessary to control the operation of an LED. The stepdown DC-DC converter includes: a reference voltage supplier for providing a reference voltage; a feedback unit for feeding back the power supply voltage on an output line; an operational amplifier for operationally amplifying the reference voltage and the fed-back power supply voltage; a switch unit for switching on/off a DC voltage on an input line toward the output line; and a charging and discharging circuit for selectively performing a charging operation of the switched voltage from the switch unit and a discharging operation of its charged voltage according to the switching operation of the switch unit to provide the power supply voltage to the output line.