Frequency compensation scheme for LDO regulator operated under wide power supply range in smart battery system

Abstract

A low dropout (LDO) linear regulator suitable for wide power supply of 4.5∼28V for smart battery system applications to generate a stable 1.8V output is presented in this paper. By utilizing pre-regulator to output a rough 3.3V as internal power supply, the proposed LDO provides less power dissipation and high stability. For the frequency compensation of the core regulator, some approaches like using output capacitor to set a dominant pole, utilizing a buffer stage to avoid generation of low-frequency pole, introducing an additional zero, are presented to stabilize the regulator loop for various load conditions and wide supply range. Besides, parasitic poles in high frequency can be compensated by feedforward compensation and mirror-pole compensation. © 2011 IEEE.