An improved universal CMOS current-mode analogue function synthesiser

A CMOS integratable current-mode analogue function synthesiser circuit is presented. The proposed circuit is based on approximating the required function using its sixth-order Taylor series expansion. These approximations can be implemented by adding the weighted output currents of a number of basic building blocks, built around a basic current squarer, and a constant current. The proposed circuit can simultaneously realise 32 different mathematical functions and can be easily expanded to accommodate many others. SPICE and Monte Carlo simulation results demonstrating the circuit performance are included.