RDR-242 - 30 W power supply

This engineering report describes a power supply using the Power Integrations® TOPSwitch®-JX TOP266VG. The power supply operates over a universal input range and provides a 12 V, 30 W output. It is designed and tested to operate in open frames at ambient temperatures up to 40 °C. By design, TOPSwitch-JX maintains nearly constant efficiency over a very wide load range, eliminating the need for special operating modes to meet specific load thresholds. This optimizes performance of existing and emerging energy efficiency regulations. Maintaining constant efficiency ensures that the design is optimized for future changes in energy efficiency regulations without the need for redesign. TOPSwitch-JX's low MOSFET capacitance enables higher switching frequencies without the efficiency loss seen with standard discrete MOSFETs. The 132 kHz switching frequency (rather than the 70 kHz to 100 kHz used for discrete MOSFETs) reduces the required transformer size, thereby reducing cost. This power supply provides the following protection features: Output OVP with latching shutdown (including open loop) Resettable overload protection This document provides complete design details including specifications, schematics, bill of materials, and transformer design and construction information. This information includes data related to regulation, efficiency, standby, transient load, power limit, and conducts EMI scans.