This part is a kind of semiconductor called LD7531A.

Function of this product has Green-Mode PWM Controller.

Manufacturers : Leadtrend Technology

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Some of the text within the PDF file :

LD7531A 7/6/2009 Green-Mode PWM Controller with Frequency Trembling and Integrated Protections REV: 00 General Description The LD7531A is built-in with several functions, protection and EMI-improved solution in a SOT-26/ DIP-8 package. It takes less components counts or circuit space, especially ideal for those total solutions of low cost. The implemented functions include low startup current, green-mode power-saving operation, leading-edge blanking of the current sensing and internal slope compensation. And the LD7531A features more protections like OLP (Over Load Protection) and OVP (Over Voltage Protection) to prevent the circuit damage from the abnormal conditions. Furthermore, the frequency trembling function is to reduce the noise level and thus helps the power circuit designers to [ ... ]

LD7531A PDF Datasheet Download