DER-096: 3.3V @ 2A, 5 and 12V @ 200mA, 48V in

This document is an engineering prototype report describing a VoIP prototype power supply utilizing DPA423P. The power supply delivers 10 W continuous from an input of 37 to 57 VDC.

The design has been optimized to minimize radiated EMI emissions.

In the EMI section of the report it can be seen that there is a dramatic improvement in radiated EMI over the existing production DPA423 design.

This document provides complete design information including specification, schematic, bill of material and transformer design and construction information. The document also provides performance information.

The power supply uses a DPA423 device (U1), with integrated MOSFET and controller, in an isolated flyback configuration. The circuit also uses the under-voltage shutdown feature of the device along with current limit setting to minimize transformer size. The device operates at a switching frequency of 300 kHz.