MP4078 is an single-stage offline controller with active power factor correction (PFC) for constant voltage output applications. The device implements primary-side regulation (PSR) control without requiring a secondary feedback circuit or optocoupler for flyback applications. It is also available for non-isolated topologies (e.g. buck-boost). The device achieves ultra-low standby power consumption. Its pulse frequency modulation (PFM) implements a minimum operating frequency under no-load conditions. The MP4078 works in discontinuous conduction mode (DCM) with valley switching for improved efficiency performance The MP4078 operates in constant-on-time (COT) mode to achieve a high power factor across the universal input. It adopts a cascode MOSFET technique to achieve fast start-up with few external components. The MP4078 integrates multiple protection features that greatly enhance system reliability and safety. The MP4078 is available in an SOIC-8 package.