Circuit and design techniques for fine-grain power management in manycore System-on-Chip (SoC) are presented. Recent advances in dynamic platform control techniques to enable (1) independent voltage-frequency domains, (2) dynamic power budget allocation to various blocks depending on workload, (3) fast dynamic voltage-frequency scaling and (4) fast activation and shutdown, are described. Future challenges and opportunities for complex manycore SoC designs with wide dynamic power-performance range, including near-threshold-voltage (NTV) operation, are summarized. Future trends in multi-voltage designs with integrated voltage regulators are highlighted.