This part is a kind of semiconductor called LN3C69.

Function of this product has HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER.

Manufacturers : Lii Semiconductor

Image and pinout :

Some of the text within the PDF file :

澎湃驅動力 源於力生美 LN3C69 HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER FEATURES uLiiSemi Proprietary Cycle Turning Technology for Improved EMI Performance. uExtended Burst Mode Control For Improved Efficiency and Minimum Standby Power Design uAudio Noise Free Operation uExternal Programmable PWM Switching Frequency and Over Temperature Protection (OTP) uInternal Synchronized Slope Compensation uLow VDD Startup Current and Low Operating Current uLeading Edge Blanking on Current Sense Input uVDD Over Voltage Clamp and Under Voltage Lockout with Hysteresis (UVLO) uGate Output Maximum Voltage Clamp (18V) uLine Input Compensated Over Universal Input Voltage Range. uCycle-by-Cycle Over-current Threshold Setting For Constant Output Power Limiting Over Universal Input Voltage Range [ ... ]

LN3C69 PDF Datasheet Download