Akros Announces Integrated PD Controller Supporting 2-Event Physical Layer Classification Per Upcoming IEEE®802.3at PoE Standard
Akros Silicon Inc. announced what it describes as the industry’s first Powered Device (PD) Controller, implementing the 2-Event Physical Layer Classification functionality of the IEEE® 802.3at standard (Draft 2.0). This upcoming PoE standard raises the maximum available PD input power to 30W from the previously specified level of 13W in the existing 802.3af standard.
The new 30W power level opens up a range of new applications for PoE, including IP Security Cameras with Power, Tilt and Zoom (PTZ) capability, new multi-radio 802.11n Wireless Access Points, WiMax Customer Premise Equipment, SOHO Ethernet Switches, Thin Clients and LCD Displays.
The 2-Event Classification allows the PD to recognize whether it is connected to a Type 1 (802.3af/13W) or Type 2 (802.3at/30W) Power Sourcing Equipment (PSE), and vice-versa. The 2-event Classification informs the IEEE® 802.3at compliant PSE that it is safe to increase power delivered to the PD from 13W to 30W. It is claimed that use of this classification protocol between Type 2 PSE and Type 2 PD enables dynamic negotiation and allocation of power, leading to more efficient system power management.
Akros Silicon has also successfully completed testing the interoperability of the new AS1135 PD Controller with Microsemi’s recently released PD64001 PSE Power Manager, in accordance with the IEEE® 802.3at-Draft2.0 standard – said to be an important milestone for the industry, as it is said to allow customers to effortlessly implement both ends of the PoE link (both PSE and PD).
The AS1135 controller is an extension of Akros’ AS1100 family, supporting many new features in the same small 5 x 5 20pin QFN package. The part provides "AT Detect" functionality on a logic output pin, indicating successful PoE connection to Type 2 PSE. This hardware feature can be used by the system micro-controller to self-configure the networked appliance based on the power delivery capability of the network. The AS1135 is also capable of operating with local power input as low as 10V.
Another new feature is the capability to externally set the switching frequency of the integrated dc-dc controller in the 100 – 500kHz range. This is said to give designers added flexibility to optimize the system for parameters like EMI, power consumption and component sizes. Lower switching frequencies can be beneficial in controlling EMI and improving no-load efficiency. Designers may also use higher switching frequencies to reduce the size of components used in the power converter output stage. These features are additions to standard features found in the AS1100 product family like integrated surge protection and low emissions dc-dc controller, to enable EMC ready system designs.
Akros offers reference designs and evaluation boards to help evaluate the performance of the AS1135. The AS1135 is available in a 20-pin 5 x 5 QFN with a Reduction of Hazardous Substance (RoHS) compliant package. The device is priced at $1.66 for 1kU quantity.
