Double-ring protection low drop out (LDO) linear voltage regulator

The invention discloses a double-ring protection low drop out (LDO) linear voltage regulator comprising the following elements: an error amplifier used for switching dual-end input into single-end output, thus providing high output gain; an over-current protection circuit used for comparing output voltage with peak voltage, and using a feedback circuit to control a power tube, thus realizing over-current protection function; the power tube realized by a PMOS transistor common-source amplifier structure and used for providing sufficient gain for the LDO loop, and ensuring the LDO drop out voltage is the PMOS pipe leakage source voltage; a unit gain frequency compensation network used for generating zero point resistance. The conduction resistance of the PMOS pipe critical work point can be reduced to drop voltage, thus providing over-current protection effect, and the error amplifier can normally work; good stability is provided; the double-ring protection low drop out (LDO) linear voltage regulator has low input-output voltage difference, can stably work when voltage and temperature change, and has the over-current protection auxiliary function.