A Low Dropout Linear Regulator with Current Limit Function

Abstract

The utility model relates to a low-dropout linear regulator with a current limiting function, which belongs to the technical field of electronic circuits. In the present invention, the grid of the power tube is connected to the current limiting module through a push-pull voltage buffer. When no overcurrent occurs, the current limiting module does not work and is not connected to the grid of the power tube, and the output of the LDO is adjusted by the error amplifier and the feedback resistor network. Voltage; when the load current exceeds the set current limit, the current limit module starts to work, quickly clamps the gate-source voltage of the power tube to a fixed value, and quickly limits the larger load current to a lower value. At the same time, when the gate voltage of the power tube is pulled down, the output voltage of the LDO will also decrease, which avoids excessive current of the power tube for a long time. The invention not only ensures that the LDO has a stable output voltage under normal conditions, but also ensures that the load current will not remain at a large value for a long time under the condition of overcurrent, avoiding the damage of the power tube and reducing the power consumption of the circuit at the same time.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and in particular relates to the design of a low dropout linear regulator (Low Dropout Regulator, LDO) suitable for high-voltage power supply rail circuits. Background technique [0002] With the development of the integrated circuit industry and the rise of portable electronic products, power management has gradually become the focus of public attention. Low-dropout linear regulator (LDO) has been widely used as a common power generation module because of its low cost, low noise, high precision and simple peripheral circuits. [0003] Such as figure 1 As shown in (a), the traditional LDO circuit is composed of an error amplifier (EA) and a feedback resistor to form a negative feedback voltage loop to control the power tube to adjust the output terminal voltage, so that it will be adjusted through the loop even when the load jumps To keep the output at a relatively stable voltage va...

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Problems solved by technology

[0005] Aiming at the problem that the load current of the above-mentioned traditional LDO is at a large value for a long time, it is easy to cause damage to the power tube. The present invention proposes a low-dropout linear regulator LDO with a current limit function, which can control the load current of the LDO. limit, avoiding the damage of the power tube, and also reducing the power consumption of the circuit

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