A novel contactless cantilever-based current sensor

This work presents a novel cantilever-based current sensor, in which a permanent magnet was integrated for interacting with the magnetic field near a current-carrying conductor. The magnetic torque leads to mechanical deflection of the cantilever which is piezoresistively detected. A comprehensive theoretical model of the current-to-voltage transduction is developed, in which the key parameters governing sensitivity and the dominant noise mechanisms are analyzed. A multi-parameter co-optimization method is used to systematically design the cantilever structure, piezoresistive elements, and process parameters. The sensor with compact footprint of 2.3 mm × 4.6 mm can simultaneously detect AC/DC with good linearity over the 0-50 A range, a high system-level sensitivity of 113.39 mV/A, and an estimated intrinsic noise-limited current resolution better than 0.1 A, therefore, has potential applications in smart meters, industrial IoT systems, and electric vehicle charging equipment.