Backup power source for Ethernet devices using Power over Ethernet technology

Abstract

Currently, the technology of Power over Ethernet becomes rather popular, mainly for powering of terminal devices. Provided these devices are used to drive larger wireless network, it is appropriate that they were provided with a backup source in case of power failure. As the voltages used by Power over Ethernet technology are compatible with voltages of standard lead-acid batteries, the construction of the backup source can be simplified by omitting the output voltage inverter. Although the simplest way of creating a backup source is just to connect the appropriate lead-acid battery in parallel to the output of the main power source, there are more convenient solutions based on switches with MOSFET transistors. More sophisticated control of the battery connecting and charging will significantly prolong its life. One of such solutions is provided within the framework of this paper. The basic concept of the backup power source provides the output voltage of 24 V, but it can be optionally equipped with converters increased this voltage up to 48 V or decreasing it down to 12 V. The description of the converters is provided as well. © 2014 North Atlantic University Union. All rights reserved.