A 400-ns-Settling Time Hybrid Dynamic Voltage Frequency Scaling Architecture and Its Application in a 22-Core Network-on-Chip SoC in 12-nm FinFET Technology

We have developed a dynamic-voltage-and-frequency-scaling (DVFS) architecture that combines a package-integrated buck voltage regulator (PIVR) with fully standard-cell-based digital low-dropout regulators (LDO) to support fine-grained control at the scale of individual cores in a 22-core system-on-chip (SoC) with a settling time of 400ns. The PIVR has a power density of309mW/mm2 and features full back-end integration of magnetic-core power inductors. During a workload study on the SoC consisting of four general-purpose RISC- V cores and 18 specialized accelerators, our hybrid voltage regulator (HVR) showed the highest power savings when compared with other power management techniques for workload durations above 1.3μs and peak power savings of 23% over the baseline without DVFS.