The universal 100 240V AC adapter output 13.5V 5A employs an isolated-flyback power-supply controller that provides Constant-Voltage (CV) using an optical coupler to improve transient response to large-load steps. The switching adapter 100 240v processes information from opto-coupled feedback and an auxiliary flyback winding for high-performance control of output voltage and current. The output voltage is regulated accurately by a high-performance voltage-mode amplifier with an accurate voltage reference. With a wide input range, the 100 240V 50 60hz adapter in fact operates from an universal input of 85-265Vac. The 100 240V AC adapter comes with excellent efficiency performance. Its power-saving technologies limit the no-load power consumption to lowest level. The precise output over-voltage and over-load protection greatly enhance the system reliability. Effective thermal management reduces thermal stress on power supply reliability, allows the 120V to 240V adapter to operate at full power in higher ambient temperatures.