Enable circuit applied to ldo linear voltage regulator

Abstract

The invention discloses an enabling circuit applied to a LDO (low-drop out) linear regulator and mainly solves the problem that an input voltage variation range of an enabling module of the LDO linear regulator is small. The enabling circuit comprises a positive voltage path (1) and a negative voltage path (2), inputs of the two circuits are connected with an enabling signal SHDN of the LDO regulator, and outputs of the two circuits are connected with input of a bias module of the LDO linear regulator. The two paths are connected within different voltage ranges of the enabling signal SHDN, in other words, when the enabling signal SHDN is higher than positive break-over threshold voltage, the positive voltage path (1) is connected, and high-potential voltage is outputted; when the enabling signal SHDN is lower than negative break-over threshold voltage, the negative voltage path (2) is connected, and high-potential voltage is outputted. The threshold range of the enabling circuit is enlarged, the enabling module can be started by input voltage within the positive voltage and negative voltage range, and flexibility in application of the LDO linear regulator is improved.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and relates to a switching analog integrated circuit, in particular to an enabling circuit, which can be used in a switching power supply chip. Background technique [0002] With the development of integrated circuits and electronic technology, a large number of portable devices have become indispensable products in people's lives. The power supply voltage of portable devices will fluctuate in a wide range during the power supply process. In order to ensure voltage stability, many electronic devices Both use a linear regulator LDO to supply power. In order to facilitate the turn-off and turn-on of the peripheral control chip, an enable pin is often added outside the LDO chip, so an enable circuit needs to be generated internally. [0003] figure 1 The block diagram of the traditional output adjustable LDO is given, in which the inside of the solid line box is the internal structure ...

AI Technical Summary

Problems solved by technology

The enabling circuit of the traditional positive voltage LDO can only be turned on within a certain range of positive voltage, and the enabling circuit of the negative voltage LDO is turned on within a certain range of negative voltage, which limits the input voltage of the enabling circuit and makes the LDO Circuit application diversification is limited

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