This part is a kind of semiconductor called MP4021.

Function of this product has Primary Side Control Offline LED Controller.

Manufacturers : MPS

Image and pinout :

Some of the text within the PDF file :

The Future of Analog IC Technology MP4021 Primary Side Control Offline LED Controller with Active PFC DESCRIPTION The MP4021 is a primary-side–control offline LED lighting controller that achieves high power factor and accurate LED current for isolated single-power-stage lighting applications in a single SOIC8 package. The proprietary realcurrent control method accurately controls LED current from primary-side information. Eliminating the secondary-side feedback components and the optocoupler significantly simplifies the LED lighting system design. The MP4021 integrates power factor correction and works in boundary conduction mode to reduce the MOSFET switching losses. The extremely low start-up current and quiescent current reduces the total power consumption and provides a high-effic [ ... ]

MP4021 PDF Datasheet Download