Introduction to Low Dropout (LDO) Linear Voltage Regulators
Linear voltage regulators are key components in any power-management system that requires a stable and ripple-free power supply. A subset of linear voltage regulators is a class of circuits known as low dropout (LDO) regulators. This paper explains the fundamentals of LDOs and introduces Vidatronic’s LDO technology which solves many of the known shortcomings of LDO circuits. LDOs are available as both stand-alone packaged devices and as intellectual property (IP) cores that can be integrated into a larger integrated circuit design. This paper deals with the fundamental principles of this class of circuits and, therefore, is applicable to both stand-alone devices and IP cores. There are several articles available regarding LDOs. While some of them are highly technical and heavy on mathematical analysis, others are generic and don’t go into any detail. This paper attempts to strike the right balance to appeal to a wider audience. Several basic aspects of these circuits are discussed, with the intention of giving the reader a simple overview, rather than delving into complicated details and mathematical derivations. The motivation for this paper is to make the readers comfortable with the topic of LDOs and to prepare them for assimilating more advanced topics. Key electrical specifications are examined and contrasted against Vidatronic’s IP cores towards the end of the article, to showcase the differentiation provided by Vidatronic.