This part is a kind of semiconductor called WS3441A.

Function of this product has Non-isolated Buck Offline LED Driver.

Manufacturers : WINSEMI

Image and pinout :

Some of the text within the PDF file :

WS3441A ProductDescription Features  Critical Conduction Mode Operation  Internal 500V Power MOSFET  No Auxiliary Winding  Ultra Low Operating Current  ±3% LED Output Current Accuracy  Efficiency up to 93%  LED Open Protection  LED Short Protection  Current Sensing Resistor Short Protection  Thermal Regulation Function  Available in SOP-8 Package Applications  LED Candle Light  LED Bulb, Spot Light  T8/T10 LED String  Other LED Lighting Typical Application Non-isolated Buck Offline LED Driver Description The WS3441A is a high precision buck constant current LED driver. The device operates in critical conduction mode and is suitable for 85Vac~265Vac universal input offline LED lighting. The WS3441A integrates a 500V power MOSFET. The operating [ ... ]

WS3441A PDF Datasheet Download