21.5 A Fully Integrated Multi-Phase Voltage Regulator with Enhanced Light-Load-Efficiency Peak of 86%, Featuring an Autonomous Mode Transition from Hard-Switching to Soft-Switching to Discontinuous Conduction Mode in 3nm FinFET CMOS

Modern-day computing systems demand a lot of power, especially driven by AI workloads. With an explosion in data size, there is a corresponding increase in the current consumption of SoCs, which can reach hundreds of Amperes [1]–[2]. This creates some unique challenges for power delivery systems. Fully integrated voltage regulators (FIVRs) provide the unique benefit of highly localized power delivery, which can help mitigate supply droop events and address current surges [3]–[7]. For data center applications, average energy consumption is affected by both peak power-hungry modes and idle low-power data retention states. When these power delivery systems are scaled to support larger workloads, the corresponding idle power consumption scales accordingly. From this, we can surmise that while peak power efficiency is an important metric for FIVRs, in recent days, FIVRs or any power delivery system must maintain high efficiency even at idle load conditions without impacting the overall transient response or the droop on the output. Prior work toward achieving this includes forcing regulator operation in soft-switching and Discontinuous Conduction Modes (DCM); however, this has the disadvantage of higher ripple and lower efficiency in high current draw scenarios [3], [7].