Short circuit detection circuit and detection method

Abstract

A short-circuit detection circuit, comprising: a detection reference setting circuit for setting a short-circuit detection reference value; a comparison circuit, receiving and comparing a short-circuit detection reference value and an output voltage sensing signal, and outputting a comparison signal, and the comparison signal is detected The reference setting circuit is used as a basis for adjusting the short-circuit detection reference value; the short-circuit determination circuit receives the comparison signal, timing detects whether the comparison signal changes within the preset time threshold, and generates a short-circuit detection signal according to the detection result ; Wherein, when the comparison result of the comparison signal exceeds the preset time threshold and does not change, the short circuit detection signal determines that an output short circuit occurs. The short-circuit detection circuit can detect the different characteristics of the output voltage of the power supply during the start-up phase. Regardless of whether the soft-start time of the output voltage of the power supply is long or short, it can accurately and quickly determine whether the output voltage of the power supply is short-circuited.

Description

technical field [0001] The invention relates to electronic circuits, 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 chips caused by instantaneous shocks. Output short-circuit detection is a common protection mechanism, while soft-start functionality that prevents excessive inrush current stress during start-up is another. In the power management chip, it is necessary to require all protection mechanisms 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 stage, so that the output voltage of the power supply increases gradually, and avoids suddenly applying a large output voltage to the load. A surge occurs that damages the device. In the power supply with soft start functio...

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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