Retiming and dual-supply voltage based energy optimization for DSP applications.

Low energy, as one of the most important metrics in modern design, has also been considered as an important criterion to many DSP applications. To address the low energy issue of DSP applications, in this work, we have proposed a new energy minimization approach which optimally combines the dual-supply voltage (dual-Vdd) with the retiming technique. We have specifically focused on various hardware-implemented transforms and filters such as the fast Fourier transform (FFT) and the discrete cosine transform (DCT) which are widely used in DSP applications. Our key idea is to use a maximum-flow/min-cut strategy to reduce the required number of flip-flop logic and while maintaining the delay of the circuit in such a way that to enable efficient Vdd allocation in the subsequent stage. The effectiveness of our approach is demonstrated on both FFT and DCT applications using an industrial cell library. Given a target delay, a significant energy saving using our approach is observed.