This part is a kind of semiconductor called 1200AP100.
Function of this product has PWM Current-Mode Controller.
Manufacturers : ON Semiconductor
Image and pinout :
Some of the text within the PDF file :
NCP1200A PWM Current−Mode Controller for Universal Off−Line Supplies Featuring Low Standby Power Housed in SOIC−8 or PDIP−8 package, the NCP1200A enhances the previous NCP1200 series by offering a reduced optocoupler current together with an increased drive capability. Due to its novel concept, the circuit allows the implementation of complete off−line AC−DC adapters, battery charger or a SMPS where standby power is a key parameter. With an internal structure operating at a fixed 40 kHz, 60 kHz or 100 kHz, the controller supplies itself from the high−voltage rail, avoiding the need of an auxiliary winding. This feature naturally eases the designer task in battery charger applications. Finally, current−mode control provides an excellent audio−susceptibi [ ... ]