A 200-MHz 4-phase fully integrated voltage regulator with local ground sensing dual loop ZDS hysteretic control using 6.5nH package bondwire inductors on 65nm bulk CMOS

This paper presents a 200MHz 4-phase fully integrated voltage regulator (FIVR) with 6.5nH package bondwire inductors. With an on-chip delay-locked loop (DLL) for phase synchronization, the proposed FIVR employs a cost-effective local ground sensing feedforward control loop for high speed load transient sensing and a ZDS hysteretic feedback control loop for accurate voltage regulation, independently achieving a dual-loop compensated operation within each sub-converter. Implemented on a standard 65nm bulk CMOS process, the FIVR delivers a peak efficiency of 84.2% at 256mW, with a maximum power density of 670mW/mm2. In response to a 280mA/120ps load step, the FIVR settles within 11ns with 78mV droop. To our best knowledge, this is 2.7 times faster than the best design despite 1.8 times larger load step, while facilitating the use of 1.3 times smaller on-chip capacitor.