This part is a kind of semiconductor called HF01B01.
Function of this product has (HF01B00 - HF01B04) Off Line High Voltage Quasi Resonant Regulator.
Manufacturers : MPS
Image and pinout :
Some of the text within the PDF file :
HF01B00/01/02/03/04 Off Line High Voltage Quasi Resonant Regulator The Future of Analog IC Technology DESCRIPTION The HF01B00/01/02/03/04 is a flyback regulator with Green Mode Operation. Its high efficiency feature over the entire input/load range meets the stringent world-wide energy-saving requirements. The HF01B00/01/02/03/04 is an integrated current mode controller with a 700V FET. Its valley switching detector ensures minimum Drain-Source voltage switching every cycle, per Quasi-resonant operation. When the output power falls below a given level, the regulator enters the burst mode to lower the stand-by power consumption. An internal minimum off time limiter prevents the switching frequency from exceeding 150kHz, which is below the CISPR-22 EMI start limit. Internal 2.4ms soft start [ ... ]