Scheduling and Optimal Voltage Selection For Low Power Multi-Voltage DSP Datapaths

For Low Power Multi-Voltage DSP Datapaths Mark C. Johnson and Kaushik Roy School of Electrical and Computer Engineering Purdue University, West Lafayette, Indiana, 47907-1285, USA [email protected], [email protected] Abstract|We present an algorithm called MOVER (Multiple Operating Voltage Energy Reduction) to minimize datapath energy dissipation through use of multiple supply voltages. In a single voltage design, the critical path length, clock period, and number of control steps limit minimization of voltage and power. Multiple supply voltages permit localized voltage reductions to take up remaining schedule slack. MOVER initially nds one minimum voltage for an entire datapath. It then determines a second voltage for operations where there is still schedule slack. New voltages can be introduced and minimized until no schedule slack remains. MOVER was exercised for a variety of DSP datapath examples. Energy savings of up to 50% were observed when comparing dual to single voltage results. The bene t of going from two to three voltages never exceeded 15%. Circuit resource requirements for multiple voltages varied greatly. In some cases requirements changed very little with respect to number of voltages, but area penalties up to 150% were observed. Implications for IC layout are discussed.