Electric Hum Signal Readout Circuit for Touch Screen Panel Applications

This paper presents a new touch sensing mechanism that detects different signals on a touch panel generated by an electric field formed from household power. Without requiring complicated transmitter and receiver circuits, a 16-channel front-end sensor and shared readout circuits are proposed to realize the new touch-sensing mechanism. This touch-sensing technique can be applied on the appliance control panel to detect the operation control. The signal readout circuit is implemented in a 0.18-μm CMOS process, which occupied an area of 2.64 mm
²
. The proposed sensing technique achieves 46.5-dB signal-to-noise ratios with finger touch. With battery power supply of 1.8 V and 2.5 V, total power consumption of the proposed readout circuit is measured as just 2 mW.