Power management ICs provide single-chip solutions for PoE
The PD77718 power manager and PD77010 power controller from Microchip provide highly integrated solutions for power-over-Ethernet (PoE), giving designers an easy way to implement the technology and comply with IEEE 802.3 standards.
Microchip has introduced its seventh generation of power-sourcing equipment (PSE) technology for PoE applications which conform to an IEEE 802.3af/at/bt industry standard. The PD77718 is a PSE manager, and the PD77010 is a PSE controller.Ā
These products are highly integrated, energy-efficient and surge-protected designs supplied in a compact form factor. The only external component required is a capacitor, helping PoE system designers to save board space and reduce bill-of-materials costs.Ā
PSE managers and controllers are widely implemented in various Ethernet networking devices, including switches, routers and gateways, as well as in specialized equipment such as digital video recorders and PoE midspans/injectors. Additionally, Microchip offers powered device (PD) controllers which conform to the specifications of the IEEE 802.3 standard.
PoE enables the transmission of both power and data over a single Ethernet cable. Networking devices such as Ethernet switches, routers and gateways supply power through a PSE chip embedded within the unit. Devices powered by PoE, such as wireless access points, incorporate a PD IC to receive this power. These two components work together to deliver power to connected devices via the Ethernet cable.
Power delivery does not commence until the PD requests it. There are eight power classes, as defined by the IEEE 802.3af/at/bt standards. The PD specifies the exact amount of power required, ranging from as little as 4 W up to 90 W at the source.
On receiving a valid power request, the PSE acknowledges and classifies the requested power before initiating delivery. Both the PSE and PD continuously monitor for faults to protect the devices. If a fault is detected, or if the device no longer requires power, the PSE will terminate power delivery.
A PoE-powered device requires three essential components:
- Diode bridge
- PD IC
- Dc-dc converter
Microchip offers the PD70288 PoE ideal diode bridge, which cuts power dissipation by more than 90% compared to standard diode bridges.