An All-Digital Fully Integrated Inductive Buck Regulator With A 250-MHz Multi-Sampled Compensator and a Lightweight Auto-Tuner in 130-nm CMOS

A 125-MHz fully integrated inductive buck voltage regulator using 11.6-nH wirebond inductance and 3.2-nF on-chip capacitance is presented in 130-nm CMOS. An all-digital architecture is presented to ease integration in digital process nodes. The IVR demonstrates enhanced bandwidth enabled by a multi-sampled digital compensator with reduced precision computation. A fast and lightweight auto-tuning engine is presented to optimize steady-state stability and transient response under variation in passives. A resistive transient assist scheme and an adaptive all-digital discontinuous conduction mode control are presented to reduce transient response time and enhance light-load efficiency, respectively. The 130-nm testchip demonstrates a peak efficiency of 71% and a 2.9-V/μs output slew during large reference transient.