This part is a kind of semiconductor called STR-A6251M.

Function of this product has Universal-Input/15 W 67 kHz Flyback Switching Regulator.

Manufacturers : Allegro MicroSystems

Image and pinout :

Some of the text within the PDF file :

g n i h tors c t i a Sw egul R STR-A6251M Universal-Input/15 W 67 kHz Flyback Switching Regulator The STR-A6251M is a 67 kHz PWM topology (with ±5% frequency jittering for minimum EMI) regulator specifically designed to satisfy the requirements for increased integration and reliability in flyback converters. It incorporates a primary control and drive circuit with an avalanche-rated power MOSFET. This is a higher-frequency version of the STR-A6251. Covering the power range from below 21 watts for a 230 VAC input, or to 15 watts for a universal (85 to 264 VAC) input, this device can be used in a wide range of applications, from DVD players and VCR player/recorders to ac adapters for cellular phones and digital cameras. An auto-burst standby function reduces power consumption at light loa [ ... ]

STR-A6251M PDF Datasheet Download