Reverse-current-prevention protection circuit of LDO (low dropout regulator)

A linear voltage regulator and protection circuit technology, applied in the direction of instruments, electric variable adjustment, control/regulation systems, etc., can solve the problems of LDO without anti-backflow, etc., and achieve the effect of improving reliability and preventing damage

Active Publication Date: 2018-11-09
NANJING MICRO ONE ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem that the traditional LDO has no anti-backflow protection circuit, the present invention provides an anti-backflow protection ci

Method used

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  • Reverse-current-prevention protection circuit of LDO (low dropout regulator)
  • Reverse-current-prevention protection circuit of LDO (low dropout regulator)
  • Reverse-current-prevention protection circuit of LDO (low dropout regulator)

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Embodiment Construction

[0015] Such as figure 2 As shown, the present invention is figure 1 On the basis of the prior art, an anti-backflow circuit Reverse Pro and an anti-backflow NMOS transistor MN are provided to prevent the current from the output terminal VOUT from flowing backward to the input terminal VIN. The anti-backflow circuit Reverse Pro is connected between the input terminal VIN of the LDO linear regulator, which is the source of the power PMOS transistor MP, the output terminal VOUT, which is the drain of the power PMOS transistor MP, and the substrate Bo of the power PMOS transistor MP, to prevent backflow The drain and source of the NMOS transistor MN are connected between the feedback resistor RF2 and the ground terminal, and the anti-backflow circuit Reverse Pro compares the potential of the input terminal VIN with the potential of the output terminal VOUT, so that the substrate Bo potential of the power PMOS transistor MP is switched and selectively connected to VIN and The hig...

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Abstract

The invention relates to a reverse-current-prevention protection circuit of an LDO (low dropout regulator). On the basis of an existing LDO, a reverse-current-prevention circuit and a reverse-current-prevention NMOS (N-metal-oxide-semiconductor) transistor are arranged, the reverse-current-prevention circuit is connected among an input terminal VIN, an output terminal VOUT and a substrate of a power PMOS (P-channel metal oxide semiconductor) transistor, a drain and a source of the reverse-current-prevention NMOS transistor are connected between a feedback divider resistor and a ground terminal, and VIN potential and VOUT potential are compared by the reverse-current-prevention circuit, so that a substrate of the power PMOS transistor is switched to be selectively connected with the highestpotential between VIN and VOUT, the parasitic diode effect fixed between the substrate Bo and the drain of the power PMOS transistor MP is broken, an output logic signal of the reverse-current-prevention circuit is connected with a grid of the NMOS transistor, a reverse current produced by the parasitic positive bias diode effect of the power PMOS transistor can be avoided between output VOUT andinput VIN, and loss and damage of the power PMOS transistor are effectively prevented.

Description

technical field [0001] The invention relates to an LDO linear voltage regulator, in particular to an anti-backflow protection circuit of the LDO linear voltage regulator. Background technique [0002] LDO linear regulators are widely used in portable electronic devices due to their outstanding advantages of simple structure, low cost, low noise, low power consumption and small package size. [0003] Traditional LDO such as figure 1 As shown, the peripheral components are composed of input capacitor CIN, output capacitor COUT, and load resistor RL. The chip includes an enable control circuit EN, a reference voltage VR generation circuit, an error amplifier EA, a current limiting circuit CurrentLimit, and feedback resistors RF1 and RF2. The working principle of LDO is: input enable EN signal to control whether the whole circuit is working or not, the output voltage is divided and sampled by feedback resistors RF1 and RF2 and input to the reverse end of the error amplifier EA,...

Claims

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Application Information

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IPC IPC(8): G05F1/56
CPCG05F1/561
Inventor 陶晓峰张洪俞任丽
Owner NANJING MICRO ONE ELECTRONICS
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