Short-circuit detection circuit and detection method

Abstract

A short-circuit detection circuit comprises a detection reference setting circuit, a comparison circuit and a short-circuit judgment circuit, wherein the detection reference setting circuit is used for setting a short-circuit detection reference value, the comparison circuit is used for receiving and comparing the short-circuit detection reference value with an output voltage sensing signal and outputting a comparison signal, the comparison signal is received by the detection reference setting circuit and is used as a basis for adjusting the short-circuit detection reference value, the short-circuit judgment circuit is used for receiving the comparison signal, detecting whether the comparison signal is changed within a preset time threshold by timing and generating a short-circuit detection signal according to a detection result, and the short-circuit detection signal is used for judging that output short circuit is generated when a comparison result of the comparison signal exceeds the time threshold and is not changed. The short-circuit detection circuit can be used for detection by matching with different change characteristics of an output voltage of a power supply at a starting stage, and whether the power supply output voltage is circuit-shorted can be accurately and rapidly determined no matter when soft starting time of the output voltage of the power supply is long orshort.

Description

Technical field [0001] The invention relates to an electronic circuit, in particular to a short circuit detection circuit and a detection method thereof. Background technique [0002] Power management chips often require various protection measures to avoid damage to the chip caused by instantaneous impact. Output short-circuit detection is a common protection mechanism, and the soft-start function to prevent excessive surge current stress from forming during startup is another protection mechanism. In the power management chip, all protection mechanisms need to be required to work effectively at the same time. [0003] The soft-start function is usually to set a soft-start voltage that gradually rises from zero to the target value as the reference voltage during the power-on phase, so that the output voltage of the power supply gradually increases, avoiding sudden application of a large output voltage to the load The device is damaged by a surge. In the power supply using the s...

AI Technical Summary

Problems solved by technology

However, with the development of electronic technology, the application environment is becoming more and more complex. For example, when the output capacitor is very large, the output voltage rises slowly. K2 times the output voltage, which is judged by the chip as an output short circuit, but the chip is actually working normally

In order to meet the application environment, some chips extend the soft-start time to achieve the desired purpose, but this not only increases the chip area, but also has a longer soft-start time in the case of a small output capacitor, which affects the chip. performance; there are also some chips that shield the output short-circuit detection and protection in the soft-start state, which in turn causes the lack of protection mechanisms

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