On-chip low dropout regulator with fast transient response function

Abstract

The invention belongs to the technical field of power source management, and relates to an on-chip low dropout regulator with the fast transient response function. The on-chip low dropout regulator comprises an error amplifier, a power tube MP, a Miller capacitor CL, a first divider resistor and a second divider resistor, wherein the source electrode of the power tube MP is connected with input voltage VIN, and the drain electrode of the power tube MP is grounded after passing through a series structure of the first divider resistor and the second divider resistor; the negative input end of the error amplifier is connected with the reference voltage Vref, the positive input end of the error amplifier is connected with the series point of the first divider resistor and the second divider resistor, the output end is connected with the grid electrode of the power tube MP, and the Miller capacitor CL is connected between the drain electrode of the power tube MP and the ground; an error amplifier of an STCB structure is adopted, and a transient enhancing structure is inserted into the input stage of the error amplifier; a differentiator is connected between the grid electrode and the drain electrode of the power tube MP, and meanwhile a self-biasing structure is introduced into the LDO. Miller capacitance needed by loop compensation is substantially reduced while transient response speed is increased.

Description

technical field [0001] The invention belongs to the technical field of power supply management, and in particular relates to the design of a low-dropout linear voltage regulator. Background technique [0002] Low-dropout linear regulator (LDO), as an important circuit in power management chips, is widely used in consumer electronics, medical electronics, aerospace and other fields due to its low noise, low cost, and low power consumption. [0003] LDO controls the power tube by amplifying the error signal obtained through output feedback to provide output current to drive the load. Its essence is a voltage-controlled current source that adjusts the load current according to the output voltage, such as figure 1 shown. Traditional on-chip integrated LDO (Cap-less LDO) includes error amplifier (EA), power transistor, resistor feedback network, and load capacitor. The basic working principle is: the resistance feedback network samples the output voltage, amplifies it after mak...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the difficulty of loop compensation under light load of traditional Cap-less LDO and the problem of too slow transient response, the present invention proposes an on-chip low-dropout linear regulator with fast transient response, by using the error amplifier of STCB structure and transient enhancement structure, which improves the transient response speed and greatly reduces the Miller capacitance required for loop compensation

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