Traditional power adapters above 75 W require a two-stage topology structure to meet the requirements of input power factor and harmonics

which has become a technical bottleneck for further improving their power density. A single-stage high power density power adapter topology was proposed in response to this issue. This topology removes the front-end PFC circuit and input electrolytic capacitor from the traditional power adapter circuit and adds an energy compensation circuit to the flyback converter. Controlling the storage and release of energy in the energy storage capacitor can achieve power factor correction while meeting the output voltage ripple requirements

effectively improving the power density of the power adapter. Based on this

a comprehensive control strategy based on one-cycle control was proposed

and key circuit parameters in the topology were designed. Finally

an 80 W system prototype was built to verify the correctness and feasibility of the proposed solution.