Low drop-out linear regulated power supply without off-chip capacitor

Abstract

The invention provides a low drop-out linear regulated power supply without an off-chip capacitor. The low drop-out linear regulated power supply comprises an error amplifier, a power tube output branch, a high-pass filtering network, a first charging and discharging circuit, a second charging and discharging circuit and a buffer at least, wherein the power tube output branch is connected with the error amplifier; the high-pass filtering network is used for regulating the driving capability of the error amplifier based on changes of the output voltage of the power tube output branch; the first charging and discharging circuit is used for being connected with a gate capacitor of a power tube to form a first charging and discharging path based on ripples in the output voltage of the power tube output branch, and the power tube output branch comprises the power tube; the second charging and discharging circuit is used for being connected with a gate capacitor of the power tube to form a second charging and discharging path based on transient jumps of the output voltage of the power tube output branch, the power tube output branch comprises the power tube; the buffer is connected with the power tube output branch. The low drop-out linear regulated power supply not only achieves stability in a full-load range, but also can achieve a low ripple voltage and rapid recovery capability under the circumstance of heavy-load current jumps.

Description

technical field [0001] The invention relates to the field of linear voltage stabilizing sources, in particular to a low-dropout linear voltage stabilizing source without external capacitors. Background technique [0002] Traditional linear voltage regulators, such as 78xx series chips, require the input voltage to be higher than the output voltage by more than 2v ~ 3V, otherwise they will not work properly. But in some cases, such conditions are obviously too harsh, such as 5v to 3.3v, the voltage difference between input and output is only 1.7v, which obviously does not meet the conditions. In response to this situation, a low dropout regulator (LDO) appeared. [0003] As a linear voltage regulator, LDO is widely used because of its advantages of low cost, low noise, and small quiescent current. Since the P-channel MOSFET is driven by voltage and does not require current; moreover, because the on-resistance of the MOSFET is very small, its voltage drop is very low, which ...

AI Technical Summary

Problems solved by technology

However, the introduction of large external capacitors undoubtedly greatly increases the area of ​​the PCB board, and also puts forward higher requirements for the integration of the system chip.

Images