A Compact Reconfigurable Resonator-Based Direct Current Sensing System

A compact and reconfigurable current readout system is presented that is based on microelectromechanical system (MEMS) resonators. The proposed system generates analog and digital outputs by electrothermally tuning the microbeam resonant frequency according to variations in the input current signal. A single resonator is utilized to generate the analog output, while a resonator array operating at different frequencies is utilized to generate a digital one-hot output. Experiments showed that the frequency shift is linearly proportional to the square of the current. The single resonator has a detection limit of $1.16 ~\mu \text{A}$ , and the resonator array offers good static linearity with a maximum differential/integral non-linearity of 0.55/0.23 least significant bits. The single resonator is suitable for applications requiring high-resolution measurements. The proposed resonator sensing system has a small footprint, is compatible with large-scale integration, and provides considerable flexibility for reconfiguration.