Design Example Report
Title
10 W Power Supply using DPA423P
Input: 37-57 VDC
Output: 3.3V/2.0A, 5V/200mA, 12V/200mA
Specification
Application
Author
VoIP phone
Power Integrations Applications Department
DER-96
Document
Number
Date
September 12, 2005
1.0
Revision
Summary and Features
This document is an engineering prototype report describing a VoIP power supply
utilizing DPA423P.
• Eliminates LM78xx linear-regulators on 5 V
• Low-cost 12 V linear-reg. with short circuit protection provided by main supply
• High Efficiency (> 70% at 48 VDC)
• Low EMI signature (both radiated and conducted emissions)
• Low Parts Count
• Built-in input short circuit protection on all outputs
• Carefully designed for low EMI
The products and applications illustrated herein (including circuits external to the products and transformer
construction) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign
patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found at
www.powerint.com.
Power Integrations
5245 Hellyer Avenue, San Jose, CA 95138 USA.
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com