This part is a kind of semiconductor called TNY178PN.
Function of this product has (TNY174 - TNY180) Offline Switcher.
Manufacturers : Power Integrations
Image and pinout :
Some of the text within the PDF file :
TNY174-180 ® TinySwitch-LT Family Energy Efﬁcient, Ofﬂine Switcher with Enhanced Flexibility and Extended Power Range Product Highlights Lowest System Cost with Enhanced Flexibility • 650 V rating optimized for non-active PFC applications • Simple ON/OFF control, no loop compensation needed • Selectable current limit through BP/M capacitor value - Higher current limit extends peak power or, in open frame applications, maximum continuous power - Lower current limit improves efﬁciency in enclosed adapters/chargers - Allows optimum TinySwitch-LT choice by swapping devices with no other circuit redesign • Tight I2f parameter tolerance reduces system cost - Maximizes MOSFET and magnetics power delivery - Minimizes max overload power, reducing cost of transfor [ ... ]