PoE Flyback Energy Provide Reference Design

The module delivers 5V and 12.5W output from a 36V to 57V enter, appropriate for numerous improvement phases and energy conversion.

Energy over Ethernet (PoE) provides energy to units related through Ethernet cables, eliminating the necessity for separate AC energy connections. This know-how not solely simplifies cabling but additionally enhances community administration of units, permits energy measurement, and removes the necessity for AC-DC conversion in numerous units corresponding to LED lights, cameras, sensors, and extra. Quite a few PoE options make the most of remoted energy provides, which guarantee steady energy supply throughout numerous functions. One instance is the MAXREFDES128 PoE module reference design from Analog Units (ADI), which outputs 5V at 2.5A (12.5W) from an enter vary of 36V to 57V. 

The module is designed for analysis, design, prototyping, and manufacturing. It contains all crucial management circuitry and electrical elements to create an remoted flyback converter energy provide with a 36V to 57V enter and a 5V, 12.5W output. The module is split into two major sections: the PD controller and the no-opto flyback DC-DC converter.

The PD controller contains a PD interface controller that complies with IEEE 802.3af/at requirements, offering detection and classification signatures and an built-in isolation energy change for inrush present management. It manages the detection and classification processes upon connection to PoE power-sourcing gear (PSE). This part additionally incorporates a power-good (PG) sign that prompts the DC-DC converter circuit, decreasing startup inrush present and warmth.

The no-opto flyback DC-DC converter employs a 60V peak present mode, a fixed-frequency switching controller designed for Discontinuous Conduction Mode (DCM), reaching a peak effectivity of 85% at a 100kHz switching frequency. It contains a primary-side MOSFET that shops vitality within the transformer’s major winding and a secondary-side synchronous MOSFET driver that replaces the everyday diode, enhancing effectivity and thermal administration.

Further module options embody startup and enter overvoltage safety settings, with a 5ms smooth begin to mitigate inrush present from the PSE. The module makes use of a resistive divider to set the switching thresholds for environment friendly operation.

The design is provided with two 6-pin connectors. It incorporates two bridge rectifiers to make sure compatibility with numerous PSE sorts, although this results in some energy loss because of the steady conduction of two diodes. Transformer specs, corresponding to these for the examined HR051455 from HanRun, could be calculated for customized designs with steering from Utility Observe 5504. This design successfully controls the timing of MOSFET operations based mostly on drain voltage, managing the present move to the output load and the discharge of the output capacitors.

ADI has examined this reference design. It comes with a invoice of supplies (BOM), schematics, meeting drawing, printed circuit board (PCB) structure, and extra. The corporate’s web site has extra knowledge concerning the reference design. To learn extra about this reference design, click on right here.