This part is a kind of semiconductor called SG3525A.

Function of this product has REGULATING PULSE WIDTH MODULATOR.

Manufacturers : Microsemi Corporation

Image and pinout :

Some of the text within the PDF file :

SG1525A/SG2525A/SG3525A SG1527A/SG2527A/SG3527A Regulating Pulse Width Modulator Description The SG1525A/1527A series of pulse width modulator integrated circuits are designed to offer improved performance and lower external parts count when used to implement all types of switching power supplies. The on-chip +5.1 V reference is trimmed to ±1% initial accuracy and the input common-mode range of the error amplifier includes the reference voltage, eliminating external potentiometers and divider resistors. A Sync input to the oscillator allows multiple units to be slaved together, or a single unit to be synchronized to an external system clock. A single resistor between the CT pin and the Discharge pin provides a wide range of deadtime adjustment. These devices also feature built-in soft-st [ ... ]

SG3525A PDF Datasheet Download