Abstract:
Along with the continuous enhancement in IC functionality, the complexity on circuit unit area is increasing. Compared with the traditional binary logic, single line of multi-valued logic circuit carries more information, which can effectively improve information processing speed and reduce the area cost of the chip. At the same time, existing studies have shown that the optimal reed-muller (RM) logic form of a logic function may have a more compact structure, less power consumption and better testability than Boolean logic form. RM logic based synthesis and optimization is getting more attention from designers and researchers in IC field. Fixed polarity reed-muller (FPRM) and mixed polarity reed-muller (MPRM) are two common kinds of expansions in multi-valued RM logic circuits. For an
n-variable ternary FPRM function, there are 3
n polarities, corresponding to 3
n expansions, which in general may be realized by 3
n circuits with diverse structure, area, power consumption and propagation delay. Ternary FPRM circuit optimization is to find the optimal circuit expansion of a specified circuit by best polarity searching. Based on research on ternary FPRM circuit expression and the invasive weed bat algorithm (IWBA), a ternary FPRM circuit delay and area optimization is proposed. Firstly, a propagation delay estimation model is established and further a fitness function for delay and area optimization is obtained. Then by applying the ternary polarity conversion technique, the ternary FPRM expansion corresponding to polarity 0 of a specified Benchmark circuit is derived from its given binary Boolean logic form and is evaluated by calculating its fitness value. Finally, the IWBA algorithm is used to search for the best polarity of the ternary FPRM circuit by computing and comparing other polarities' fitness. 10 Benchmark circuits and their simulation data are listed in this paper, which show that compared to the data by original bat algorithm, propagation delay by IWBA is saved 14.3% in average, and circuit area is saved 66.0% in average.