Microchip Claims to Have Solved Power Over Ethernet Interoperability Issues with New PoE ProductsOctober 24, 2019 by Gary Elinoff
New solutions enable both legacy and IEEE 802.3bt-2018-compliant devices to be powered via existing Ethernet frameworks.
Industry is rapidly adapting the new IEEE 802.3bt-2018 standard for delivering PoE (power over Ethernet). This leaves users with a dual challenge. They must first enable the older, existing PDs (powered devices) to work well with the newer PDs designed for the new standard. They must also, very often, do so within an existing Ethernet infrastructure.
For network users, Microchip's new series of offerings include network switches and midspans. The network switches, or injectors, are used to provide the data and power to be transmitted over the Ethernet cables to the PD’s, or devices to be powered. If an existing network switch doesn’t provide power, a midspan, inserted between the network switches and the PD, can be purposed to do so.
The Microchip PD69210 and PD69208T4. Image from Microchip.
For system developers, Microsemi now offers PSE (power sourcing equipment) chipsets. With these, designers will be able to provide up to 90W of power, without changing switches or cabling, for both pre-standard and IEEE-compliant PDs.
The need to avoid tearing down well-functioning infrastructure is paramount. As described by Microchip business unit manager Iris Shuker, “...our PSE chipsets offer a unique architecture that eliminates the need to redesign system boards or offer separate pre-standard and IEEE-compliant product lines. They are also at the heart of our IEEE 802.3bt-2018-compliant PoE injectors and midspans that bridge the interoperability gap for users."
The PSE Chipset
The new chipset enables support for two-pair and four-pair systems with a single-board design. They provide all manager and controller functionality needed for building highly interoperable PSE equipment that can source between 90 to 99.9 watts of power supporting up to 48 ports. Applications include IEEE 802.3bt Type 3 (Classes 1-6) as well as Type 4 (Classes 7-8).
The PD69208M is a single-chip device accommodating eight ports. It supports standard PD detection, power-up, and protection according to IEEE802.3 and the HDBaseT standards. It also accommodates legacy/pre-standard PD detection.
The PD69204T4 is designed to be employed in Ethernet switches and midspans. Like the PD69208M, it enables devices to receive both power and data over the same cable. The PD69204T4 supports four ports.
The PD69208T4 supports 802.3bt Type 4, which can deliver slightly more power.
The PD69210 is a PoE Controller designed to work with the three PSE managers listed above. This device employs an ESPI bus to connect to as many as 12 PSE managers. It communicates to the host CPU via I2C or UART interface.
Software Upgrade Microchip’s Gen 6 PSE Chipset
As part of the Microchip’s effort to promote interoperability, a software upgrade is available for pre-standard PSE designs that were based on the company’s Gen 6 PSE chipset. With this upgrade, the older designs can be upgraded to IEEE 802.3bt with no hardware changes.
The PSE chipsets are available now. Availability for the injectors and midspans is projected for November 2019.
Support for Bringing Products to Market Faster
In an effort to cut down on design time for engineers, the company has made evaluation boards, firmware, GUI software, and communication protocols available to users.
An example PoE application for the new devices. Image from Microchip
PoE Devices Around the Industry
Power over Ethernet is attracting wide interest, and why not? Who wants to have a separate cable for power when it can readily be provided over modern Ethernet cables?
The PM8804 and PM8805 from STMicroelectronics provide converter circuitry for PDs requiring up to 71 watts of power. The units are primarily targeted at 5G “small cells,” WLAN access points and routers, as well as smart-building and smart-office applications.
Have you designed with PoE before? Tell your peers about it in the comments below.