Automatic switching circuit for main power source and backup power source

Abstract

The invention discloses an automatic switching circuit for a main power source and a backup power source. The automatic switching circuit is composed of a power output terminal, a PMOS power source change-over switch, a first control logic unit and a power monitoring module. The power monitoring module determines whether a main power source meets a power supply requirement; if so, a main power source supply enabling signal is outputted to a first control logic unit; if not, whether a backup power source meets a power supply requirement is determined; and if so, a backup power source function enabling signal is outputted to the first control logic unit. The first control logic unit controls the main power source to output power to a power output terminal after receiving the main power source supply enabling signal and controls the backup power source to output power to the power output after receiving the backup power source supply enabling signal. The power monitoring module is used for comparing voltages of the main power source and the backup power source to select one power source with the higher voltage to provide power for the first control logic unit. Therefore, switching from the backup power source with the higher voltage to the main power source with the lower voltage is realized automatically. Moreover, the circuit is simple; the reliability is high; and the cost is low.

Description

technical field [0001] The invention belongs to the field of electronic technology, and in particular relates to an automatic switching circuit for a main power supply and a backup power supply. Background technique [0002] With the development of electronic technology, various industries have higher and higher requirements for power supply reliability. Many important application scenarios require uninterrupted power supply. Most uninterruptible power supply systems are composed of a main power supply and a backup power supply. Generally, the main power supply is Direct current, backup power source is battery. After the main power supply is lost, the electronic equipment can still operate normally under the backup battery power supply. The switching technology between the main power supply and the backup power supply is widely used in dual power supply application scenarios. [0003] The traditional power switching scheme uses the single-phase conduction characteristic of...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defect of complex circuit structure when the high-voltage backup power is switched to the low-voltage main power in the power switching mode based on MOS switches in the prior art, and to provide a kind of main power and backup power that can Automatic switching circuit of main power supply and standby power supply with simple circuit structure, reliable circuit and low cost

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