Low-dropout regulator
A low-dropout regulator (LDO regulator) is a type of a DC linear voltage regulator circuit that can operate even when the supply voltage is very close to the output voltage. The advantages of an LDO regulator over other DC-to-DC voltage regulators include: the absence of switching noise (in contrast to switching regulators); smaller device size (as neither large inductors nor transformers are needed); and greater design simplicity (usually consists of a reference, an amplifier, and a pass element).