Power-on reset circuit and power supply unit

Abstract

The invention provides a power-on reset circuit and a power supply device. The power-on reset circuit comprises an overvoltage detection unit and a timing unit, wherein the overvoltage detection unitis connected with a voltage output end of the power supply and is used for generating an overvoltage indication signal when the voltage output by the voltage output end is detected to be larger than or equal to a preset voltage; and the timing unit is connected with the overvoltage detection unit and is used for starting timing when the overvoltage indication signal is received and generating a power-on reset marking signal after the timing time is elapsed, wherein the timing time can be adjusted. According to the power-on reset circuit and the power supply device, timing can be directly started when the overvoltage indication signal S1 is received through the timing unit arranged at the rear end of the overvoltage detection unit, so that an external microcontroller does not need to perform controlling, and it does not need to start to work before the power supply is powered on; besides, the timing time can be adjusted according to actual conditions, and the work is flexible and convenient.

Description

technical field [0001] The invention relates to the technical field of power-on reset of a power supply, in particular to a power-on reset circuit and a power supply device. Background technique [0002] When the power supply (such as LDO (linear regulated power supply)) works at the critical point of power-on reset completion or the zero point before PLL (phase-locked loop) is stable, the analog circuit needs to give a sign signal to the matched digital circuit to It means that from the moment mentioned, the output of the power supply and the PLL are stable, thereby ensuring the reliability of the circuit system. [0003] In the currently applied LDO circuit, the main structure of the POR (Power On Reset) circuit mainly has the following types: one is to use a capacitor, and use the characteristic of the voltage exponential rise when the capacitor is charged to control the voltage rise process. The power-on reset time of the first circuit is long and uncontrollable; the se...

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to provide a power-on reset circuit and power supply device, which solves the problem that the timing unit in the existing power-on reset circuit adopts a soft-start timing circuit arranged in an external micro-controller. Controller control, need to start working before the power is turned on, and the timing cannot be adjusted according to the actual situation

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