In t'his paper we will consider how to select an optimal set of supply voltages and account for level conversion costs when optimizing the schedule of a resource domina.ted data path for minimum average power dissipation. Integer linear program (ILP) and non-linear program (NLP) formulations are presented for a minimum power schedule under latency and throughput constraints. Results are presented for several data path topologies under minimum latency constraints and under more relaxed latency constraints. The optimization demonstrated substantial benefit going from one to two supply voltages, but minimal additi,onal benefit from any additional supplies. For example, a Kalman filter benchmark produced a power estimate of 356.7mW for a single 5V supply, 265.4mW for 4V and 5V supplies, but no additional improvement for three supplies. Increasing minimum schedule latency by 50% improved optimization results substantially for two and three supply voltages but in mod cases there was no improvement at all for a single optimal supply voltage.

Date of this Version

March 1996