This engineering report describes a notebook adapter power supply employing the Power IntegrationsTOPSwitch-JX TOP269EG. This power supply operates over a universal input range and provides a 19 V, 65 W output. It has been designed and tested to operate in a sealed enclosure in an external ambient temperature environment of up to +40 °C.The TOPSwitch-JX, by design, maintains virtually constant efficiency across a very wide load range without using special operating modes to meet specific load thresholds. This optimizes performance for existing and emerging energy-efficiency regulations. Maintaining constant efficiency ensures design optimization for future energy-efficiency regulation changes without the need for redesign.