AN453 TDE1897C，TDE1897R，TDE1898C和在极端过载条件下的TDE1898R

AN453 TDE1897C，TDE1897R，TDE1898C和在极端过载条件下的TDE1898R

AN827
APPLICATION NOTE
A 500W HIGH POWER FACTOR WITH THE L4981A
CONTINUOUS MODE IC



The widespread use of passive AC/DC off-line converters causes low power factor and high line current
harmonic distortion. To reduce these phenomena and to comply with relevant regulatory agency require-
ments , designers are employing active power factor correction in their off-line SMPS applications. This
paper describes a practical, low cost and easy to implement 500W power factor corrected application
that employs the L4981A Continuous Mode PFC IC.


INTRODUCTION
Reduction of line current harmonic distortion and improvement of power factor is of great concern t