Growing the IoT means higher power to PoE
As IoT continues to grow, so will power over ethernet (PoE). Silicon Labs showed some of their latest PoE powered devices over the weekend, with improved efficiency and power. Keep reading to find out more.
Written by Steve Taranovich from EDN
At APEC today, Silicon Labs showed off their two new power over Ethernet (PoE) powered device (PD) families, Si3406x and Si3404. These devices are designed with high integration and efficiency to serve a broad range of IoT applications.
These families have all necessary high-voltage discrete components on a single PD chip; the solutions support IEEE 802.3 at PoE+ power capabilities, have flexible power conversion options with more than 90 % efficiency, sleep/wake/LED support modes, and excellent EMI immunity.
Next gen PoE PD systems will see limitations and delays
More power is needed for the next generation of designs with the IoT in mind.
Figure 1 IP cameras, wireless access points, IP phones, and smart lighting use PoE (Image courtesy of Silicon Labs)
I spoke to John Wilson, senior manager of PoE Products at Silicon Labs, about the new PD developments that are being demonstrated at APEC this year. 2018 will be a big year for PoE because the next generation of the standard is expected to be ratified by the IEEE committee around June or July. This new standard will raise the power levels to 100W, which will be paramount for the lighting market.
Companies like Philips have LED PoE luminaire lighting products already and it would be to their advantage, as well as other lighting companies who want to have smart lighting fixtures with PoE and sensors that might provide data over the Ethernet with such information as temperature and humidity. Analytics may ride on top of that in the retail space identifying where a customer is in relation to sales people on the floor at that time. This could show that most customers spend a great deal of time in the front of the store but their sales people are mostly located in the rear of that store. That analytics overlay on top of the PoE-enabled lighting structure is a key part of the value proposition in an IoT and PoE power/smart network play. Silicon Labs has 30W products right now in that ‘sweet spot’ in the market.
Cameras, in security and surveillance, are growing more than 20% year-on-year; wireless access points at 15% year-on-year (feature-rich video IP phones, public hot spots, advanced 802.11 wireless access points, and smart home appliances)
Design engineers like more integrated solutions of such devices with good power conversion efficiency and Silicon Labs excels in those areas. Legacy products have high voltage on chip like transient voltage suppressors, input diode bridges, and power MOSFETs enabling direct connection to an Ethernet RJ-45 connector. Along with this, the company has raised their power conversion efficiency from a legacy 70% to 90% with these new ICs, which also support isolation. EMI has also been vastly improved to allow quicker time-to-market.
These applications require higher wattage driving increased demand for PD devices that support the PoE+ standard. For example, the latest motor-positioned IP cameras with pan/tilt/zoom and heater elements create heavy loads on power supplies. PoE+ technology brings 30W of power to support these demanding application tasks. Surge resiliency up to 4kV is key, especially in the China market where cameras are deployed externally with Ethernet cables running inside the building to the outside exposed to potential lightning strikes. See Figure 2 for an IP camera power system example.
Silicon Labs’ Si3406x family is the ideal PD interface solution for new classes of PoE+-enabled IoT products in residential, commercial, and industrial environments.
Figure 3 This portfolio addresses all PoE+ PD use cases (Image courtesy of Silicon Labs)
This family also integrates all power management and control functions required for a PoE+ PD application, converting the high voltage supplied over a 10/100/1000 BASE-T Ethernet connection to a regulated, low-voltage output supply. The new architecture minimizes PCB footprint and external BOM cost by enabling the use of economical external components while still maintaining high performance.
The regulator’s switching frequency is tunable with a simple external resistor value to avoid unwanted harmonics. An integrated synchronous driver can control a secondary side field effect transistor (FET) to improve power conversion efficiency. Connection to a PSE switch is maintained during sleep mode by an automated maintain-power-signature (MPS) feature.
Complementing the Si3406x family, the Si3404 IC offers cost-effective, 802.3 Type 1 compliant support for lower power 15W PoE PD applications. The Si3404 includes all interface and control functions required for low-power PD applications in a very small footprint.
Figure 4 Si404 and Si402 products (Image courtesy of Silicon Labs)
Silicon Labs also has an excellent variety of PoE PD reference designs, helping designers to deploy critical power supply subsystems to market faster.
Figure 5 Class 3 Si3404 to high-power Class 4 Si34061 EVBs (Image courtesy of Silicon Labs)
Class 2-4 development kits
- Si3404 Isolated Class 3 Evaluation Kit Si3404ISOC3-KIT
- Si3404 Buck Class 2 Evaluation Kit Si3404BKC2-KIT
- Si3406 Non-IsoFlybackClass 2 Evaluation Kit Si3406FBC2-KIT
- Si3406 Non-IsoFlybackClass 3 Evaluation Kit Si3406FBC3-KIT
- Si34061 Isolated Class 4 Evaluation Kit Si34061ISOC4
Tools information can be found here.
Pricing and packaging
Samples and production quantities of the Si3406x ICs are available now in low-profile, 5×5 mm QFN packages, and the Si3404 device is available now in a low-profile, 4×4 mm QFN package. Si3406x product pricing in 10,000-unit quantities begins at $1.34 (USD), and the Si3404 is priced at $1.02 (USD) in 10,000-unit quantities. To help developers reduce development time and cost, Silicon Labs offers a range of isolated and non-isolated Class 2-4 evaluation kits for Si3406x and Si3404 devices with prices starting at $79 (USD MSRP).
For more information about the Si3406x and Si3404 families and evaluation kits and to order product samples, visit the Silicon Labs website.
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