A 199 μW, 82.9% Efficiency Current Driver with Active Common-Mode Reduction for Impedance-Based Tactile Sensors

This paper presents a differential current driver based on a current feedback structure, designed to drive hydrogel sensors. It achieves low power consumption, low common-mode signal on the load, and high current efficiency. The use of a negative unit gain buffer reduces the common-mode signal on the load arising from process variations. The current driver was designed in a 65-nm CMOS technology with a 3.3 V supply. Simulation results demonstrate a THD of 0.4% at 125 kHz, for 40 μA
p-p
output current. The common-mode voltage on the load is reduced by 98.96% compared to a conventional topology using two independent drivers. The total current consumption is 60.3 μA, resulting in a current efficiency of 82.9%. The simulated output impedance is 2.76 MΩ at 125 kHz and 1.47 MΩ at 300 kHz.