Power Electronics

HDBaseT Boosts Home Consumer Electronic Networking

HDBaseT allows transmission of uncompressed full HD digital video, audio, 100BaseT Ethernet, power and various control signals onto a single 100m Cat5e/6 cable. Power over HDBaseT (PoH), a key element of the HDBaseT standard, employs technology similar to PoE with proven capability in enterprise networking.

Many IT managers will be happy about a new networking technology that allows them to connect consumer electronics (CE) equipment in their homes the same way they may connect industrial systems at work. This networking technology is HDBaseT, intended for transmission of uncompressed high-definition video, audio, 100BaseT Ethernet, and various controls throughout a home. This digital home networking system connects and networks CE devices such as set-top boxes, DVD players, Blu-ray Disc players, personal computers, video game consoles and AV receivers to compatible digital audio devices, computer monitors, and digital televisions. HDBaseT supports all TV and PC video formats, including standard, enhanced, high-definition, and 3D video.

A recent addition to the original specification is Power over HDBaseT, or PoH. This enables the transfer of DC power, along with data signals, over a single Ethernet cable in a manner similar to Power over Ethernet (PoE). In fact, PoH is based on the IEEE 802.3at standard with appropriate modifications that enable safe delivery of up to 100 W over the four-pairs of Ethernet cable. PoH defines the power source equipment (PSE) and the powered device (PD), as well as detection and protection mechanisms that ensure safe and reliable delivery of power over the HDBaseT network.

Sending power over the same Cat5e/Cat6 cable provides the option to forgo plugging devices into the wall for ac power, which allows greater mobility. Power over HDBaseT is backwards-compatible with existing Power over Ethernet (PoE) technology and Power over Ethernet Plus (PoE+) as specified in the IEEE802.3at-2009 standard.

HDBaseT delivers different types of control signals with different purposes, starting from CEC that operates basic functionality such as power-on, power-off and play/stop, to RS-232/USB and IR that operate remote equipment even when it is located in a different room.

This networking technology connects home entertainment systems and devices using a feature called 5Play™ that enables:

  • Up to 10.2 Gbps of uncompressed video
  • Audio
  • 100BaseT Ethernet
  • Control signals
  • DC power

They all share the same cable, across distances up to 100m using standard RJ-45 connectors (Fig. 1).

HDBaseT can support up to eight, 100m cable hops. Also, it can double the resolution of today’s video content, features required for 3D integration and future 2K and 4K formats. Unlike other technologies that require a specific cable or a new, proprietary connector, HDBaseT uses the existing Cat5e/6 infrastructure.

The RJ45 connector works with both HDBaseT and Ethernet. Instead of having three connectors (AC+Ethernet/RJ45+HDMI) that you find in many TV’s today, you will move to only one connector (HDBaseT/RJ45). Short circuit protection for the DC input already exists inside the PoH (and PoE) PSEs as part of their standard.

HDBaseT power capabilities also solve the problem manufacturers have faced with providing thinner, lighter wall-mounted TVs that have been encumbered by complicated companion AC-to-DC and DC-to-DC-circuitry with a single, convenient DC-to-DC power circuitry. HDBaseT replaces this AC-cable/connector so that, for instance, wall-hung TVs connected via an HDBaseT-enabled Cat5e/6 cable will require no other power source.

While defined with the consumer market in mind, PoH will most likely be extremely useful in applications in which the TV or display signage monitor is located in hard-to-reach places, such as hospital bedrooms, public dining areas, transportation locations, etc.

Powering capabilities are increasingly important as more electronic devices enter the home. This technology has enough headroom to power the vast majority of these products. For instance, today’s typical 40-inch LED TV consumes 70W and, beginning in September 2011, the latest Energy Star™ 5.3 specifications will restrict all TVs to 108W, regardless of screen size, with 40-inch and smaller TV’s consuming under 75W. Energy Star 6.0 is targeting a cap of 85W for all screen sizes from mid-2012. LCD and LED TV monitors are rapidly approaching an average of approximately one watt per inch of screen size. At these levels, HDBaseT has ample power delivery capabilities, even for supporting very large displays.

Additionally, HDBaseT’s power-delivery technology provides the foundation for new opportunities to manage overall power consumption and efficiency. These capabilities are enabled by the underlying PoE technology that has become a critical element of the latest PoH specification.

PoE Power, Efficiency

The original, low power IEEE802.3af standard used two out of the four pairs of wires existing in a Cat5e cable, while the more recent IEEE802.3at-2009, or PoE+ specification, allows power to be delivered over all four pairs. These latest PoE specifications also add mechanisms for device detection, classification, disconnection and protection from overload/short conditions, while also adding many new advanced, smart energy-management capabilities.

In a typical PoH implementation, the PSE is installed and powered by a 50 to 57 VDC power supply, and all PDs then receive power directly over the HDBaseT link across all four pairs of Cat5-or-better cables. Four-pair powering is the key to delivering more power with greater efficiency. Defined in the latest high-power PoE standards, four-pair powering gives PDs two power interfaces so they can receive twice the power of earlier two-pair solutions by using all four pairs of Ethernet cable (Fig. 2). Nothing precludes the two power interfaces to be connected−one over the two pairs using lines 1, 2, 3 and 6, and the other using the two pairs that use lines 4, 5, 7 and 8. This is what makes it possible to increase power delivery while fully complying with the standard.

Additionally, core PoE technology has been enhanced for the PoH specification to include a higher current of almost 1 A for every two pairs, with an appropriate three-event classification that identifies PoH PSEs. This enables PoH technology to transfer of up to 100W of continuous DC power, per port, from one side of the HDBaseT link to the other. Unlike in PoE, where the PD must assume a worst-case cabling infrastructure at all times, PoH enables the PD to identify the cable length/resistance and draw more power, as long as the overall power consumption does not exceed 100W. PoH is fully backwards-compatible with the IEEE802.3at-2009 PoE specification, including the section 33.7.1 mandate that all PSEs conform to IEC 60950-1:2001 and be (VA) per port classified as a Limited Power Source (LPS) carrying no more than 100 W without the need for special over-current protection devices. PoH also does not infringe on any of the mandated PoE safety requirements.

To further support PoH solutions, PoE-enabled equipment called midspans have become a popular option for commercial applications such as display signage, in which a single 24-port PoH midspan can be used to power 24 PoH capable displays. Network administrators use midspans that feature remote PD monitoring and configuration capabilities to significantly reduce power consumption system wide. They can monitor per-port and total power consumption, and configure their PDs for instant and scheduled ON-OFF functions on a port-by-port basis. The major advantage of adding PoH (or PoE) to a network via Midspans, instead of PoE switches, is that the Midspan creates virtually no disruption to the network: no re-configuration of switches or VLANs is necessary.

Although developed as a point-to-point technology for the home, HDBaseT also allows cascading and single point-to-multipoint distribution supporting both daisy chain and star topologies. Its flexibility makes HDBaseT as an ideal commercial connectivity technology for applications such as digital signage. For example, an airport installation with multiple displays are spread throughout the terminal. Using LAN cables with daisy chain and star topologies allows distribution of departure and arrival data. Controlling the entire HDBaseT-enabled system can also be done easily using Ethernet or RS-232 when applicable.

Connecting devices within a large suite or accommodating a large conference within a hotel, the existing Ethernet infrastructure allows an HDBaseT network to be easily implemented. Using HDBaseT, professional installers can network displays and devices throughout hotel suites, lobbies and conference rooms to create a unified viewing experience for guests. With all devices located in a separate space 100 meters away, flat screen displays can be easily mounted, allowing for additional traffic area, less cable clutter, and a more aesthetically pleasing space.

HDBaseT technology, with its support for daisy chain and star topology networking, is ideal for various camera applications that require a reliable solution with the highest video quality and real-time performance, at a minimal installation cost.

For instance, installing multiple surveillance cameras spread over a large outdoor area usually requires long distances and resistance to extreme environmental conditions. With HDBaseT enabled cameras, installers now have a long-reach, reliable, single-wire camera connection.

Related Articles

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Isolated 12-Port Power over Ethernet PSE Controller Chipset

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