Enhanced Grounded Capacitor Multiplier and Its Floating Implementation for Analog Filters

A current-mode capacitor multiplier using a differential amplifier with exponential current scaling is presented. The proposed circuit consists of a reduced implementation of a multiplier based on differential amplifiers with decreased need for parameter matching compared with a conventional structure, thus reducing the power consumption and silicon area. It includes an exponential current scaling scheme to provide a large multiplication factor. Additionally, the differential input stage offers the capability to implement a floating realization for bidirectional applications. The circuit operates with a minimum supply of a gate-source voltage and two saturation voltages of a transistor, making it suitable for low-voltage applications. Experimental results from a fabricated prototype in 0.5-μm technology show the operation of the grounded and floating realizations, as well as their performance when implemented in a second-order low-pass analog filter.