Low dropout linear regulator

Abstract

The invention discloses a low dropout linear regulator which comprises a bleeder circuit, an error amplifier, an output transistor, and a current feedback circuit, wherein the bleeder circuit is used to generate a feedback voltage according to an output voltage of the low dropout linear regulator; the error amplifier comprises a first input end and a second input end, receives a reference voltage and the feedback voltage, compares the feedback voltage with the reference voltage and generates a drive voltage from an output end according to the comparison result; the output transistor comprises a first which is in coupled connection with the output end of the error amplifier as well as second end which is in coupled connection with the bleeder circuit and outputs the output voltage; and the current feedback circuit comprises an input control end and a current output end, the input control end receives the output voltage, the current output end is in coupled connection with the first input end of the error amplifier, and the current feedback circuit responds to changes of the output voltage and generates a feedback current to the first input end of the error amplifier. The low dropout linear regulator disclosed by the invention has a quicker response speed, can quickly restrain the changes of the output voltage, and the output voltage is kept stable.

Description

technical field [0001] The invention relates to the technical field of power management, in particular to a low dropout linear regulator (Low Dropout Regulator, LDO). Background technique [0002] Low-dropout linear regulators have the advantages of low cost, stable output voltage, low output ripple, low noise, and no electromagnetic interference, so they are widely used in communication equipment, automotive electronics, and medical equipment. [0003] figure 1 It is a schematic diagram of a traditional low dropout linear regulator structure. like figure 1 As shown, the traditional low-dropout linear regulator includes an error amplifier EA1, a voltage divider circuit, and an output transistor T. The system controls the output voltage V through a voltage divider circuit (including resistors R1 and R2) O Perform voltage division sampling to generate feedback voltage V FB . One input of the error amplifier EA1 receives the feedback voltage V FB , the other input receiv...

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Problems solved by technology

For example, when the load current changes sharply, the output voltage V O It will also change sharply. This change is fed back to the input terminal of the error amplifier EA1 through the voltage dividing resistor, and the response of the error amplifier EA1 takes a certain time, so that the gate of the output transistor T cannot quickly respond to the sharp change of the output voltage. Affects the stability of the output voltage and the response characteristics of the low dropout linear regulator

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