Power over Ethernet (PoE) is a continually developing technology that allows delivery of both electrical power and network communications through a single cable. It is used for a variety of reasons and with a variety of powered devices.
Power over Ethernet (PoE) enables power to be delivered over the same ethernet cable. It is generally used with data communication systems that are independent of cross-talk, interference, or corruption of the data streams.
This reference design illustrates an end-to-end power tree for an IP network camera. This camera is powered using PoE or 12-V adapter based on the TI’s DaVinci™ Digital Media Processor. This design is applicable to different application processors. The power tree also derives rails required for different peripherals of an IP network camera such as Image sensor, motor control, Ethernet PHY, RS485 interface, IR LED illumination, audio, motion sensing and the alarm interface. The design can be incorporated into a complex system that requires hassle-free wiring.
The design consists of a Power-over-Ethernet (PoE) Powered Device (PD) with
integrated DC/DC, Synchronous Buck Converters with Switch and low noise and high PSRR LDO. It can generate different voltage rails required for an IP network camera.
The Power-over-Ethernet (PoE) powered device (PD) is an IEEE 802.3at Type-1 design. It provides an output power of up to 13-W. It has an integrated current-mode DCDC controller which is optimized for flyback topology.
The design integrates a synchronous step-down buck converter with forced PWM feature. All these functions are combined in a SOT-563 package. This package provides the designer with a compact size solution. The device is optimized for reduced output voltage ripple, fast transient response and higher efficiency.
The design features an input operating voltage of up to 60 Volts. According to the input voltage, the output voltage of the device can vary from 11.8 Volt up to 12.6 Volt. The design features an efficiency of up to 89 per cent. The device can provide a continuous current output of one ampere.
The design features two power tree implementations on the designed module. For higher efficiency, the design uses a mid-range buck converter for the conversion of 12-V to the required voltage. For decreasing cost, the design uses low input range buck converters for the conversion of 12-V to 5-Volt. Both of these power trees use buck converters with FPWM
mode. It provides a faster transient response to the system for handling dynamic load switching. It is required on rails that supply power to MPU. It features low output voltage ripple on voltage rails with tolerances at the MPU cores and DDR RAM.
This reference design provides a complete set of downloadable documents such as a comprehensive design guide, schematic, Altium PCB layout files, bill of materials (BOM), test results, and Gerber files that help system designers in the design and development of their end-equipment systems.