IEEE802.3bt compliant PoE PSE isolated power supply reference board

Power over Ethernet (PoE), which is mainly used in industrial and consumer devices, was defined by the IEEE802.3af (PoE) and IEEE802.3at (PoE+) standards and has been used in a wide range of applications such as IP cameras / wireless access points. It has been. Meanwhile, IEEE802.3bt (PoE++), which can supply high power, was standardized, and the power available for Ethernet networks has increased significantly.

For industrial equipment, it is essential to isolate the power supply for reliability reasons to prevent unexpected failures from affecting the entire system. Sourcing Equipment (PSE) has strict accuracy requirements, and there is no reference design on the market, so the design is difficult, and the current situation is that we cannot enjoy the cost benefits of PoE because we purchase and implement module products.

About the IEEE802.3bt (PoE++) standard

PoE supports different standards depending on the power supply side (PSE) and the power receiving side (PD), and the latest IEEE802.3bt (PoE++) extends power supply to 90W.

standard	PoE IEEE802.3af	PoE+ IEEE 802.3at	PoE++ IEEE 802.3bt
Type	Type1	Type2	Type3/4
Class	0~3	4	5~8
PSE supply power	15.4W	30W	45W~90W
PD input power	12.95W	25.5W	40W~71.3W

IEEE802.3bt (PoE++) Compliant PSE Isolated Power Reference Board

We have recently developed a reference board that specializes in PSE isolated power supplies of the IEEE802.3bt (PoE++) standard, which can be evaluated for power supply via closed networks such as industrial robots and switching hubs.

The output accuracy of the isolated power supply is that it can supply 55.8V/1.7A (90W) from a typical power supply input of 12V, and you can use this reference design in your PSE circuit without any custom design.

Product Specifications

This reference board is a forward converter circuit that uses LT8310 and LT1431 from Analog Devices.The primary and secondary sides are isolated by a custom isolation transformer 750345284 from Wurth Elektronik and a photocoupler MOC207M from onsemi. Wurth Elektronik's 74437529203221 is used for the secondary inductor.

item	specification	remarks
name	LT8310 PoE PSE Isolation power board
type name	ALT8310PSEISOREF
input voltage	12.0V
output voltage	55.8V (54.75V~57V output possible)	Compatible with IEEE802.3bt (PoE++) and LTPoE++
output power	90W(1.7A)
Power supply circuit method	Forward converter isolation circuit	Composed of LT8310, LT1431
Board outline	120mm x 90mm

PoE evaluation configuration

By combining this reference board with the Analog Devices PoE evaluation kit DC2685B-KIT, you can perform a comprehensive PoE evaluation in a 12V power supply environment for industrial equipment (4 ports compliant with IEEE 802.3af, 802.3at, and 802.3bt). ) is now possible.