Biologically-Inspired Optimization of Circuit Performance and Leakage: A Comparative Study

State-of-the-art technologies in very large scale integration (VLSI) allow for the realization of gates with varying energy consumptions and hence delays (i.e., processing speeds) in the very same circuit. By considering this technological advent as an option, the design process can pursue two different goals: (1) making the circuit as fast as possible and (2) making non-time-critical gates slower in order minimize the circuit’s overall energy consumption. This paper utilizes evolutionary algorithms, a population-based heuristic optimization technique, in order to find optimal solutions. From a technological point of view, this goal can be accomplished by varying the individual threshold voltages, which determine both the device’s processing speed and its leakage currents. The experimental results indicate that evolutionary algorithms yield significantly better solutions than rather traditional optimization algorithms. By maintaining populations of candidate solutions, evolutionary algorithms are able to escape from sub-optimal designs, which contrasts traditional single-point optimization approaches.