A fast transient voltage regulator design with all ceramic output capacitor for mobile microprocessors

Abstract

The need to have fast transient response of the voltage regulator is driven by the increasing current slew rate of the mobile microprocessor. Hence, optimizing the switching frequency of the voltage regulator becomes an important step to achieve a balance between preserving the efficiency of the voltage regulator and improving the transient response. Besides, output capacitor solution with multilayer ceramic capacitor has also become more popular due to its small size and cheap cost. A fast transient voltage regulator with all ceramic output capacitors for mobile microprocessor is proposed in this study. The outcome of the study shows that the voltage regulator designed is stable with the proposed type and number of multi-layer ceramic capacitors. More importantly, the actual transient results correlate well with the simulation results in which minimal transient droop and overshoot are observed with a dynamic current load step with a slew rate of 10.5 A/1 μs.