Automatic switching circuit of power supply

Abstract

The invention discloses an automatic switching circuit of a power supply, which comprises a first power input terminal, a second power input terminal, a switching module and an output terminal, wherein the first power input terminal adopts local direct current power supply input, one path thereof is directly connected with the output terminal, and the other path thereof is connected with a first input terminal of the switching module; the second power input terminal is connected with a second input terminal of the switching module, the output of the switching module is connected with the output terminal, and when input is conducted at the first power input terminal, the switching module does not have output. The priority of the output of the first power input terminal is higher than that of the second power input terminal; the automatic switching circuit is not limited to the switching selection between a local power supply and a POE power supply, and can be extended to similar occasions with the problem of switching selection of two paths of power supplies so as to realize automatic switching between two power supplies; and the automatic switching circuit is simple and practical, has low cost and high reliability, and also has the functions of power supply voltage electrifying buffering, overcurrent protection, anti-inversed connection protection, filtering, noise isolation and the like.

Description

technical field [0001] The invention relates to an automatic switching circuit of a power supply. Background technique [0002] At present, in the 48V power supply of ONU (Optical Network Unit, optical network unit) equipment in the field of GPON / EPON (Gigabit-Capable Passive Optical Network / Ethernet Passive Optical Network) optical communication access network, the more commonly used ones are local power supply and Ethernet There are two power supply methods (POE, Power over Ethernet), and most devices only use one of them. POE power supply is a technology that can provide the power required by the ONU device through the network cable in the Ethernet, so that the original network cable can not only transmit data, but also be used as a power cable. In general, devices using Power over Ethernet do not need to obtain power from the local power supply. However, in some cases, such as the power over Ethernet module of the ONU device is damaged, or for the convenience of debuggi...

AI Technical Summary

Problems solved by technology

[0003] The invention patent with application number 200710186392.5 proposes a power switching device between POE power supply and local DC power supply, but the invention can only be used for switching between POE power supply and DC power supply, and cannot realize non-POE standard power supply and DC power supply. Switching between power supplies, and the circuit is more complicated and the cost is higher

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