I. Introduction
Capacitive touch sensors are essential for user interfaces of mobile devices, such as smart phones and tablets. The energy efficiency of capacitive touch sensors should be optimized due to their battery-powered operation. For high-quality touch features, the number of sensing channel has been increased in touch screen panels (TSPs). This, in turn, requires fine-pitch arrangements of sensing channels, getting a reduction of sensing capacitors. Furthermore, as the size of the TSP increases, the sensing condition is aggravated, resulting in an increase of power. Nevertheless, high signal-to-noise ratio (SNR) with fast scan rate is required for seamless interaction even under the condition of reduced sensing capacitors.