A Flexible Low-Power 130 nm CMOS Read-Out Circuit With Tunable Sensitivity for Commercial Robotic Resistive Pressure Sensors

This paper presents a flexible and low-power Read-Out Circuit (ROC) with tunable sensitivity, designed to interface a wide range of commercial resistive pressure sensors for robotic applications. The ROC provides contact detection, monitoring small capacitance variations at low pressure (<100 mbar), and encodes pressure measurement on 8 bit, evaluating resistive variations. Two all-digital circuits implement the conversion of the input resistance and capacitance-to-frequency, exploiting an on-chip ring oscillator as timing reference. A 130 nm RFCMOS prototype (with an active area of ) has a power consumption of 27.2 , for V. Using digital control inputs, the ROC allows a wide range tuning of measurement sensitivity (6.7–46.4 mbar/LSB) and adjustable acquisition time (226.6–461.7 and 648–890 , for contact detection and pressure evaluation, respectively). The read-out time of ms is compatible with human response after touch.