Improved Low-Voltage Low-Power Class AB CMOS Current Conveyors Based on the Flipped Voltage Follower

A high performance class-AB CMOS second generation current conveyor (CCII) suitable for low-power and low-voltage operation is proposed and simulated. The circuit is aimed to be used for sensor signal conditioning and it is based on the flipped voltage follower. Compared to the class-A CCII based on the flipped voltage follower, static power consumption is reduced significantly because driving capability is no longer limited by the biasing current, but only depends on the aspect ratio of the transistors driving current at nodes X and Z. All the high performance characteristics such as accurate voltage copy between X and Y terminals, low output impedance, high input impedance, low total harmonic distortion and wide bandwidth are retained. A modified structure with improved dynamic range for higher voltage supplies, based on the folded version of the flipped voltage follower called super source follower, is also presented. Simulation results demonstrate performance of the proposed designs.