Modeling power consumption in arithmetic operators
Résumé
The authors first address the following issues: why a voltage transition causes power dissipation, what causes a transition, what are useful and redundant transitions, how information redundancy may reduce the number of transitions, how to make information redundant by adding dependant bits, how to statistically measure the average number of transitions (or activity) and reduce it through redundancy. Then they concentrate on addition and answer the following questions: how to compute the average activity using statistics, how to model activity in the simplest adder: the carry ripple adder, how to extend the model to carry select adder, to carry lookahead adder and finally how to make adders redundant.