Power supply switching circuit

Abstract

The invention discloses a power switching circuit which comprises a first switch, a third switch, a fourth switch, a first self-locking anti-backflow circuit, a first interlocking circuit and a firstinterlocking anti-backflow circuit. The input ends of the first switch, the first interlocking circuit and the first interlocking anti-backflow circuit are respectively used for being connected with apower supply A. The input ends of the third switch and the first interlocking circuit are respectively used for connecting a power supply B, the output end of the third switch is respectively connected with the output ends of the first self-locking anti-backflow circuit, the fourth switch and the fourth switch, and the output end of the first switch is connected with power supply output. The output end of the first self-locking anti-backflow circuit is connected with the first switch, the output end of the first interlocking circuit is connected with the third switch, and the output end of the first interlocking anti-backflow circuit is connected with the fourth switch. The power conflict problem of the monitor during power supply of multiple power supplies can be solved, the reverse protection function is achieved, the circuit structure is simple, and good application prospects are achieved.

Description

technical field [0001] The invention relates to the field of film and television shooting equipment, in particular to a power switching circuit which switches automatically according to priorities. Background technique [0002] At present, monitors in the field of film and television shooting usually use two power supply methods: external DC power supply and battery plate power supply. In actual use, only the switching and protection of these two power sources need to be considered. [0003] With the demand of the market, 4K monitors began to enter the market, which brought about the increase of monitor power. In order to ensure the reliable operation of the monitor, the default power supply mode of the monitor is changed to the built-in AC-DC module power supply, but in order To adapt to the use environment of each user, it is also necessary to provide an external DC power input interface and a battery plate interface, so that the monitor has three power supplies for switch...

AI Technical Summary

Problems solved by technology

[0003] With the demand of the market, 4K monitors began to enter the market, which brought about the increase of monitor power. In order to ensure the reliable operation of the monitor, the default power supply mode of the monitor is changed to the built-in AC-DC module power supply, but in order To adapt to the use environment of each user, it is also necessary to provide an external DC power input interface and a battery plate interface, so that the monitor has three power supplies for switching and protection, so the previous design cannot meet the requirements, so a new circuit design is required , to meet the use requirements

[0004] For this reason, the Chinese patent whose application number is 2015108723569 and whose patent name is "A Three-Power Automatic Switching Circuit" provides a technical solution. In the state where the power supply exists, the detection signal 1 is output to the logic selection circuit, and then the power supply B / C is judged in the detection circuit 2, and the detection signal 1 is output to the logic circuit, and the power supply A / C is judged in the detection circuit 3, and the detection signal 3 is output To the logic circuit, the logic circuit analyzes the three detection signals, controls three independent switching circuits, and outputs, so the entire circuit system is very complicated, with many components, which is not conducive to design and understanding

Moreover, most of the under / overvoltage protection circuits in the existing designs are completed by op amp circuits and single-chip microcomputers, and there are often under / overvoltage values ​​that are unstable and have deviations in the implementation of op amp circuits.

In the technical scheme of the single-chip microcomputer, it is also necessary to provide a suitable power supply for the single-chip microcomputer, and an accurate and stable voltage value is required for reference, which is inconvenient for specific implementation

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