On-chip point-of-load voltage regulator for distributed power supplies

Abstract

An ultra-low area, current efficient voltage regulator appropriate for distributed point-of-load voltage regulation in high performance integrated circuits (ICs) is described in this paper. The proposed voltage regulator is a hybrid combination of a switching voltage regulator and a linear voltage regulator. The voltage regulator can supply over 100 mA current while generating 0.9 volts from a 1.2 input voltage. The current efficiency exceeds 99% while the load regulation to a step current ranges between 40 ns and 60 ns. No output capacitor is required to ensure stability. Hence, the required on-chip area is as small as 0.026 mm^2 for the proposed voltage regulator which is approximately four to six times smaller than area efficient low dropout regulators. The proposed circuit therefore provides a means for distributing multiple local power supplies across an integrated circuit, maintaining high current efficiency and small area.