A power supply selector for energy- and area-efficient local dynamic voltage scaling

In systems-on-chip, dynamic voltage scaling allows energy savings. If only one global voltage is scaled down, the voltage cannot be lower than the voltage required by the most constrained functional unit to meet its timing constraints. Fine-grained dynamic voltage scaling allows better energy savings since each functional unit has its own independent clock and voltage, making the chip globally asynchronous and locally synchronous. In this paper we propose a local dynamic voltage scaling architecture, adapted to globally asynchronous and locally synchronous systems, based on a technique called Vdd-hopping. Compared to traditional power converters, the proposed power supply selector is small and power-efficient, with no needs for large passives or costly technological options. This design has been validated in a STMicroelectronics CMOS 65nm low-power technology.