Design of high performance powered device for power over ethernet system

Converter efficiency is vital point in PoE system, as the PSE provided power is limited by IEEE 802.3af/at standard. Besides, the existent power loss through the Ethernet wires and PD interface added another level on the requirement to enhance the solution efficiency. This paper proposes a new topology that meets the IEEE 802.3af/at-compliant powered device (PD) solution for Power over Ethernet (PoE) systems. This topology called four switches single inductor differential output synchronous buck converter. The main advantage of the proposed solution that it reduces the stress over the switches so they can be integrated. This introduces a efficient converter with minimizing the solution footprint, reduces external BOM cost, and offers a low external part count PD solution while maintaining high performance. The proposed converter has been investigated and compared to the conventional synchronous buck converter. The proposed system has been design based on 0.18μm CMOS technology. Results show an enhancement in the system efficiency overall operating conditions. 20% improvement in the light load at low input voltage is obtained.