Kit Aids Development of Multi-Class PoE Powered Devices

REFERENCE DESIGN RUNDOWN

Kit Aids Development Of Multi-Class PoE
www.powerint.com
A new reference design kit for Powerover-Ethernet (PoE) Powered Devices (PDs) combines a multi-class PoE interface and dc/dc switching circuit built around the company's monolithic DPA-Switch family of ICs.Fully compliant with the IEEE 802.3af standard for PoE PDs, the kit supports the design of all current classes of PoE PDs (Class 0 to Class 3) and a power range up to 12.95W. According to the company, designers can change the class of a design by replacing a single resistor. The design carries out PoE signature and classification functions, while the integrated DPA-Switch device manages all the primary dc/dc switching and control functions. The complete circuit requires only 16 components and is said to cost about one-third less than designs based on integrated PoE interface/controller ICs. The PoE Class 2 PD Reference Design Kit (DAK-86) is available from the company and its authorized distributors. Pricing is $100. The design kit contains a 3.3 V, 2 A Class 2 power supply, samples of the DPA-Switch family and design software plus a comprehensive engineering report including a circuit description and schematic, test results and transformer design information.
POWER INTEGRATIONS INC.,
San Jose, CA. (408) 414-9200

Key Component
The DPA-Switch IC Family
A highly integrated solution for dc/dc conversion applications for 16 to 75 Vdc input. The DPA-Switch cost effectively integrates a power MOSFET, PWM control, fault protection and other control circuitry onto a single CMOS chip. High performance features are enabled with three user configurable pins. Hysteretic thermal shutdown is also provided. In addition, all critical parameters (i.e. current limit, frequency, PWM gain) have tight temperature and absolute tolerance, to simplify design and reduce system cost.

Note: An expanded version of Reference Design Rundown, which includes the schematic of the DAK-86 kit can be found on the EEPN web site at www.eepn.com in the June online issue.

TEST REPORT
The DAK-86 circuit was tested by the University of New Hampshire Interoperability Consortium (UNH-IOC) using a comprehensive suite of power sending equipment (PSE), and was shown to meet IEEE 802.3af requirements in all cases. Copies of the UNH-IOC test reports, along with additional information on Power Integrations' PoE offerings and complete information on the DPA-Switch family of ICs, can be found on the Power Integrations website at www.powerint.com/poe.htm.
Enter No. 111 at www.eepn.com

See Associated Figure