Practical device for expanding input voltage range of small-power switch power supply

Abstract

The invention relates to a practical device for expanding an input voltage range of a small-power switch power supply. The practical device comprises an overcurrent protection circuit, a power line filtering circuit, a rectification circuit, an overvoltage detection and negative resistance generation circuit, a voltage-limiting chopping circuit, a diversion and reverse blocking circuit and a filtering energy storage circuit, wherein a front end of the power line filtering circuit is connected with the overcurrent protection circuit, a rear end of the power line filtering circuit is connected with a front end of the rectification circuit, a rear end of the rectification circuit is connected with the overvoltage detection and negative resistance generation circuit and the voltage-limiting chopping circuit, a rear end of the overvoltage detection and negative resistance generation circuit is connected with a control end of the voltage-limiting chopping circuit, a rear end of the voltage-limiting chopping circuit is connected with the diversion and reverse blocking circuit, and a rear end of the diversion and reverse blocking circuit is connected with the filtering energy storage circuit. The practical device has the advantages of stable and reliable performance, universality, low cost and low self power consumption, the whole power system becomes more stable and reliable and is more universal, the practical device can be completely fused into the small-power switch power supply and can also be used as a preposition device of the small-power switch power supply, so that the voltage supply range of a conventional small-power switch power supply is expanded to be AC85V-AC440V and even wider.

Description

[0001] 【Technical Field】 [0002] The invention relates to a practical device for widening the input voltage range of a low-power switching power supply. [0003] 【Background technique】 [0004] Low-power switching power supplies with an output power of 5 watts and below have the advantages of light weight, simple structure, stable performance, wide input voltage, high efficiency, and low cost. They are widely used in industrial instruments and small household appliances, but As the power supply of industrial instruments, it also has the following problems: [0005] The circuits of such low-power switching power supplies are generally made in the form of single-ended flyback. At present, there are a large number of mature single-ended flyback monolithic integrated circuits to choose from, which are limited by integrated circuit technology and cost. The input voltage range of this type of circuit is limited to AC85 to AC265V. The line voltage of domestic industrial alternating current...

AI Technical Summary

Problems solved by technology

In many cases, even if the factory site can provide 220V voltage, due to the unbalanced three-phase load and the high impedance of the neutral line of the power supply, the voltage provided by the factory site is often polluted and unstable. Failure or damage of power supply

In some foreign countries, the power voltage is as high as AC440V, while in some areas, the civilian power voltage is as low as AC85V, which poses a challenge to the power supply design of industrial instrument products exported to foreign countries.

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