Advanced design and optimization of current mode blocks

This article deals with the topology modifications and the optimization of the current mode building blocks for an analog part of the video signal (HDTV) preprocessing unit. The blocks of our interest are the Current Conveyor (CCII) as the basic functional block for current mode filters and the Caprio structure translated to CMOS for an implementation of low input impedance differential current input. The topology of the current conveyor was modified to enlarge output impedance and bandwidth. The Caprio structure was, in the first step, modified to operate as a current follower in the CMOS process. After the hand setting of the circuit parameters of both structures, they were optimized to improve their operation via Differential Evolution (DE) algorithm. The proposed blocks were simulated in 0.25 um CMOS process and they operate from under 1.8 V of symmetrical supply voltage. Along with the transconductance amplifiers, the investigated structures will be utilized in current mode anti-aliasing filter for the video applications