A novel leakage-estimation method for input-vector control

Input-vector control (IVC) can be used to reduce the static power dissipation of circuits or subcircuits that are idle. In actual microprocessors, many functional units are included multiple times and not in use continuously (e.g. multiplier, ALU) dissipating static and dynamic power. As the static power dissipation depends on the actual input state, IVC can be used to apply the optimal input vector (IV) that causes the lowest static power dissipation in case the unit under consideration is idle. In order to find the optimal input vector, time-consuming simulations for all possible input vectors are inappropriate for actual circuits with data-width of more than 32 bit. Statistical approaches only include a subset of all possible input vectors and are able to finish in acceptable time, but may miss the optimal input vector. In this paper, we introduce a method that qualitatively estimates the static power dissipation in a very fast way such that all possible input vectors are taken into account without requiring time-consuming computations. The Method has been validated experimentally using a 90 nm technologies.