A Novel Ultra-Low-Power Low-Voltage Femto-Ampère Current Mirror

Abstract

A novel femto-ampere current mirror/negative impedance converter (FACMNIC) is proposed in this paper. It is shown that extremely large output impedance approaching infinite value and also negative impedances of different values can be remarkably obtained just by adjusting the built-in positive feedback loop gain. Operation of this circuit is based on two approaches called here as source voltage shifting and channel conduction manipulation. Although those two techniques are briefly explained in this paper but due to their strong action worth extensively studying and exercising. Deliberately having been composed of both current mirror and negative impedance converter capabilities in the same structure causes the proposed circuit to have a simple structure prohibiting large chip area consumption while favorably preserves following unique features. At 0.9 volt power supply it produces very small currents down to 4.6 fA and consumes an ultra-low power of 86 nW, thus it is the best choice for Ultra-Low-Power Low-Voltage (ULPLV) applications. It also exhibits the outstanding high output impedance of 400 GΩ when it is optimized for best performance operation, otherwise it can be adjusted so as to produce very high output impedances (approaching infinite values). Due to the inclusion of positive feedback, Monte Carlo analyses are performed to ensure the stability and robustness of the circuit’s operation in the presence of the PVT (process, voltage and temperature) variations. Simulation results in TSMC 0.18 μm CMOS technology with HSPICE are presented to demonstrate the validation of the proposed current mirror.