Fast and reliable short-circuit protection method and circuit for switching power supply

Abstract

The invention discloses a quick and reliable short-circuit protection method and circuit of a switch power supply. The circuit comprises a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, a first triode, a second triode, an optical coupler, a voltage-regulator tube and a diode. By means of the circuit, the power supply output loop voltage can be detected timely, if the short-circuit situation of an output loop does not happen, the optical coupler keeps conducting, the voltage-regulator tube is not broken down, and a triode interlock circuit does not work; when the short-circuit situation of a power supply output loop happens, conducting of the optical coupler is cut off, the voltage-regulator tube is broken down, and the triode interlock circuit works, after the power supply work voltage falls and breaks the switch power supply starting voltage, the switch power supply stops working, so that the short-circuit protection effect is achieved, the quick and reliable short-circuit protection method and circuit of the switch power supply are sensitive in responding and capable of quickly responding to the short-circuit and effectively avoiding the fault phenomenon occurring in the power supply device. The circuit is less in outside elements, low in power consumption, low in cost, simple in circuit structure, and capable of quickly responding to the short-circuit and reducing the failure rate of switch power supply products.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to a fast and reliable short-circuit protection method and circuit for a switching power supply. Background technique [0002] With the current maturity of the power supply industry, especially switching power supplies have been widely used in various fields. Due to its small size, low cost, light weight and high conversion efficiency, switching power supplies are widely used in various electronic devices such as industrial control, communication office, and home consumption. Since the switching power supply is an integral part of any system and affects the stable operation of the entire system, the various protection functions of the switching power supply, especially the short-circuit protection as one of the important functions, have attracted more attention. [0003] The general method of short-circuit protection is to detect voltage or current at the output terminal. When the ...

AI Technical Summary

Problems solved by technology

However, this approach has the following defects: 1) There are many peripheral circuit components, resulting in high power consumption and high cost of the circuit; 2) When the switching power supply is short-circuited, the pin response speed is not fast enough, which increases the failure rate of power supply products, which in turn affects the power supply. The safety of the product work, and even bring physical hazards to the staff

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