A touch screen controller controlling a capacitive touch screen includes a first comparator that compares a reference signal with a sensing signal, and generates a first output signal. The capacitive touch screen includes capacitive touch sensors connected to a sensing line and a drive line, and that sense a touch event. The sensing signal is output from the sensing line. The touch screen controller further includes a filter that generates a second output signal by integrating the first output signal in each sensing cycle of the filter, an analog-to-digital converter that converts the second output signal to a digital signal, and a controller that determines at least one of whether a noise is generated and whether the touch event is generated based on a reference digital signal and the digital signal, and that adjusts the number of the sensing cycles of the filter based on a result of the determination.