Sub-microsecond adaptive voltage scaling in a 28nm FD-SOI processor SoC

Abstract

This work presents a RISC-V system-on-chip (SoC) with integrated voltage regulation and power management implemented in 28nm FD-SOI. A fully integrated switched-capacitor DC-DC converter, coupled with an adaptive clocking system, achieves 82-89% system conversion efficiency across a wide operating range, yielding a total system efficiency of 41.8 double-precision GFLOPS/W. Measurement circuits can detect changes in processor workload and an integrated power management unit responds by adjusting the core voltage at sub-microsecond timescales. The power management system reduces the energy consumption of a synthetic benchmark by 39.8% with negligible performance penalty and 2.0% area overhead, enabling extremely fine-grained (<;1μs) adaptive voltage scaling for mobile devices.