Capacitive touch screens have become the dominant user interface over the past decade. Achieving high framerates with low power consumption remains a critical design goal for touch systems. The conventional charge-recycling technique reduces driving power by 64%, but it relies on off-chip capacitors. To address this issue, we propose a tri-level energy recycling scheme, in which energy released during the 2-to-1 transition is recycled to power the 0-to-1 transition on the complementary channel. This approach achieves a 25% power reduction using on-chip transmission gates. Additionally, a compressive sensing method is introduced to selectively process touched RX channels while bypassing the others, reducing the number of fine ADCs by a factor of four compared to conventional two-step sensing. The proposed techniques are implemented in a 65 nm CMOS process and integrated into a 32×20 channel prototype occupying 2.4 mm². Measurement results show that the chip consumes only 2.6 mW at a framerate of 1513 Hz. The signal-to-noise ratio (SNR) reaches 49.7 dB for finger touch and 28.7 dB for a 1 mm Φ stylus, resulting in an energy efficiency of 10.66 pJ/step.

The ubiquitous and continuous natural processes of water absorption and evaporation have stimulated interest in generating electricity through the creation of a flow of electrical charge, which can then be collected and stored. However, the resultant low output power density as well as the complicated fabrication and operation processes have hindered the practical applications of this technology. Herein, we demonstrate a highly efficient self-operating hydroelectric nanogenerator (HENG) that produces electricity through the absorption and evaporation of seawater. The single HENG consists of a hydrophilic wool cloth stripe functionalized with ketjen black powders and equipped with two electrodes affixed at its ends. The continuous absorption and evaporation of seawater results in the generation of electricity that can be stored in a capacitor. A series of 16 HENGs, each consisting of 10 stacked wool cloth stripes, can generate sufficient power to charge a supercapacitor to 1.6 V within 5 h 30 min under ambient conditions, outperforming most comparable devices reported. The superior performance observed for the HENG is attributable to the hydrophilicity and porosity of wool cloth which can continuously absorb seawater at a desired rate as well as the 2D structure of ketjen black and its high conductivity. This work paves the way to facilitate the development of HENGs for practical applications.