Low-dropout linear voltage regulator

Abstract

The invention discloses a low-dropout linear voltage regulator. The low-dropout linear voltage regulator is characterized in that a Vref output end of a reference circuit is respectively coupled with a Vref1 input end of a quick start circuit and a Vref3 input end of a turn-back current limiting circuit; the quick start circuit is used for denoising a reference voltage and outputting a control signal, a Vref2 output end of the quick start circuit is coupled with a Vref4 input end of the LDO main body circuit, and a control signal Ctrl output end of the quick start circuit is coupled with a Ctrl input end of the turn-back current limiting circuit; the turn-back current limiting circuit samples the output current and the output voltage, and when the output current exceeds a limit value, fixed current limiting and output current returning are carried out; the LDO main body circuit generates stable output voltage, and the Vout output end of the LDO main body circuit supplies power to a subordinate load. According to the invention, by arranging the quick start circuit, a control signal is output while quick start is carried out, and the turn-back circuit is ensured not to work during initial power-on, so that the circuit is prevented from entering a latch state in the rising process of the voltage of the Vout output end; normal starting of the circuit is ensured, current-limiting protection is carried out, and the reliability of the circuit is improved.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a high-reliability low-dropout linear regulator. Background technique [0002] Power management chips occupy an indispensable position in the semiconductor field. Among them, low-dropout linear regulators (Low Dropout Regulator, or LDO) can provide stable output voltages, and have low noise, high power supply rejection ratio, and low It is widely used in various high-performance power supply systems and various electronic products due to its low cost and other advantages. [0003] The output voltage of the low dropout linear regulator may become unstable due to abnormal operation of the load circuit. Especially when the load circuit is overloaded or even short-circuited, the excessive output current will easily damage the power management chip and the back-end load module. Therefore, it is usually necessary to introduce a current-limiting protection circuit. The curr...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the problem of poor reliability existing in the above-mentioned existing low-dropout linear voltage regulator, and provides a low-dropout linear voltage regulator with a reasonable structure, which generates a control signal to control the foldback circuit through a fast-start low-pass filter circuit , to prevent the circuit from entering the "latch-up" state, thereby ensuring the normal startup of the circuit and improving reliability

Images