Low Power Fast Transient Response Low Dropout Voltage Regulator

Abstract

The invention provides a low-power-consumption and low-drop-out voltage regulator capable of performing transient state response and relates to the field of analogue integrated circuits. The low-power-consumption and low-drop-out voltage regulator comprises an error amplifier connected with an input bias current source, an output power tube with the input end connected with the high-level input end and a feedback ratio resistor set, wherein the connecting point of the output power tube and the high-level input end serve as a final output end. The low-power-consumption and low-drop-out voltage regulator is characterized in that a first amplification module, a transient state response discharging access module and a driver module are arranged between the error amplifier and the output power tube. The output voltage recovery time in the transient state load changing process from big to small is effectively shortened.

Description

technical field [0001] The invention relates to the field of analog integrated circuits, in particular to a low dropout voltage regulator with fast transient response. Background technique [0002] The low-dropout voltage regulator is an important part of the power management circuit. It is usually used in the post-stage of the DC-DC switching circuit as a point-of-load power supply to provide a stable and reliable power supply voltage for the point-of-load. Due to its small voltage drop , high PSRR, low cost and other advantages, it has been widely used in portable electronic products. [0003] In the field of portable applications, in order to extend the battery power supply time: In terms of system design, by introducing the enable shutdown function, in a specific working mode, only some modules work, and some modules are in the off state, so in the process of switching between different working modes , the load current will jump instantaneously, from a few milliamps to ...

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Problems solved by technology

[0004] In addition, it is also very important to improve the conversion efficiency of the low dropout voltage regulator itself. The two main parameters that affect the conversion efficiency of the low dropout voltage regulator are the low dropout voltage and the quiescent current. The low dropout voltage requires an increase in the power tube area, which will cause the power tube The gate capacitance is too large, and the low quiescent current will affect the slew rate of the gate charge and discharge, thus affecting the loop load transient response speed

Traditional low dropout voltage regulator structures such as figure 1 As shown, V OUT Peaks are generated when the load changes transiently. Due to the limited quiescent current limit of the op amp, the output power tube gate V G The charge and discharge delay will be large, V OUT It takes a certain amount of time to restore stability. The common improvement method for low-power low-dropout voltage regulators is to increase the quiescent current of the op amp. However, for high-current voltage regulators above 1A, the grid capacitance of the power tube is large. The quiescent current improves the transient response, which will greatly increase the quiescent power consumption of the entire LDO, so traditional low-dropout voltage regulators cannot balance low power consumption and fast load transient response at the same time

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