This part is a kind of semiconductor called TOP234Y.

Function of this product has (TOP232 - TOP234) Intergrated OFff-line Switcher.

Manufacturers : Power Integrations

Image and pinout :

Some of the text within the PDF file :

TOP232-234 ® TOPSwitch-FX Family ® Design Flexible, EcoSmart®, Integrated Off-line Switcher Product Highlights Lower System Cost, High Design Flexibility • Features eliminate or reduce cost of external components • Fully integrated soft-start for minimum stress/overshoot • Externally settable accurate current limit • Wider duty cycle for more power, smaller input capacitor • Line under-voltage (UV) detection: no turn off glitches • Line overvoltage (OV) shutdown extends line surge limit • Line feed forward with maximum duty cycle (DCMAX) reduction rejects ripple and limits DCMAX at high line • Single resistor sets OV/UV thresholds, DCMAX reduction • Frequency jittering reduces EMI and EMI filtering costs • Regulates to zero load without dummy lo [ ... ]

TOP234Y PDF Datasheet Download