DESCRIPTION
The L4981 I.C. provides the necessary features to achieve a very high power factor up to 0.99.
Realized in BCD 60II technology this power factor corrector (PFC) pre-regulator contains all the control functions for designing a high efficiency-mode power supply with sinusoidal line current con
sumption.
The L4981 can be easily used in systems with mains voltages between 85V to 265V without any
line switch. This new PFC offers the possibility to work at fixed frequency (L4981A) or modulated
frequency (L4981B) optimizing the size of the in put filter; both the operating frequency modes
working with an average current mode PWM controller, maintaining sinusoidal line current without
slope compensation.

■ CONTROL BOOST PWM UP TO 0.99P.F.
■ LIMIT LINE CURRENT DISTORTION TO < 5%
■ UNIVERSAL INPUT MAINS
■ FEED FORWARD LINE AND LOAD REGULATION
■ AVERAGE CURRENT MODE PWM FOR MINIMUM NOISE SENSITIVITY
■ HIGH CURRENT BIPOLAR AND DMOS TOTEM POLE OUTPUT
■ LOW START-UP CURRENT (0.3mA TYP.)
■ UNDER VOLTAGE LOCKOUT WITH HYSTERESIS AND PROGRAMMABLE TURN ON THRESHOLD
■ OVERVOLTAGE, OVERCURRENT PROTECTION
■ PRECISE 2% ON CHIP REFERENCE EXTERNALLY AVAILABLE
■ SOFT START