This part is a kind of semiconductor called LD7750A.

Function of this product has High Voltage Green-Mode PWM Controller.

Manufacturers : Leadtrend

Image and pinout :

Some of the text within the PDF file :

LD7750A 06/25/2010 High Voltage Green-Mode PWM Controller with Over Temperature Protection Rev. 00 General Description The LD7750A integrates several functions of protections, and EMI-improved solution in a tiny package to minimize the component counts and the circuit space. The device provides functions of low startup current, green-mode power-saving operation, leading-edge blanking of the current sensing and internal slope compensation. Also, the LD7750A features more protections like OLP (Over Load Protection), OVP (Over Voltage Protection), and OTP (Over Temperature Protection) to prevent the circuit being damaged under abnormal conditions. The LD7750A features built-in auto-recovery function for OVP on Vcc pin and OLP. Furthermore, the LD7750A features frequency swapping to depress [ ... ]

LD7750A PDF Datasheet Download