A Current-Mode Digital AOT 4-Phase Buck Voltage Regulator

A synthesizable digital adaptive on-time (AOT) 4-phase buck voltage regulator (VR) for digital systems is presented. A current-mode digital AOT controller with the proposed ripple-injection schemes allow a fast and stable output voltage regulation, a fixed switching frequency operation, and phase synchronization for a multiphase VR. The digital AOT controller is implemented in the area of 0.0054 mm
²
using digital standard cells in an automated digital-design flow. The proposed VR achieves an 80-mV droop with a recovery time of 80 ns and greater than 85% power-conversion efficiency over a 50 mA to 1.2-A load current range.