This part is a kind of semiconductor called AP3790.

Function of this product has COMPATIBLE AC/DC PSR CONTROLLER.

Manufacturers : Diodes

Image and pinout :

Some of the text within the PDF file :

NEW PRODUCT A Product Line of Diodes Incorporated AP3790 PUMP EXPRESSTM COMPATIBLE AC/DC PSR CONTROLLER Description Pin Assignments The AP3790 is a high accuracy and low cost switching mode power supply controller to drive power bipolar transistor for battery charger/adapter applications. The controller regulates the output voltage and current in the primary side by piece-wise Pulse Frequency Modulation (p-PFM) in discontinuous conduction mode (DCM). The controller uses adaptive source current to optimize driving current to reduce driving loss. The system operating frequency reduces linearly from heavy load to light load in each interval of the pPFM, and enters constant current mode when the load current is equal to the maximum system output current. The output voltage of AP3790 can be [ ... ]

AP3790 PDF Datasheet Download