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

L4981B屬于集成電路（IC） > PFC（功率因數(shù)校正）。意法半導體（ST）集團制造生產(chǎn)的L4981BPFC（功率因數(shù)校正）功率因數(shù)校正 (PFC) 是用于調(diào)整交流電路中的電壓和電流之間的相位角，使之趨近于零的半導體器件。不同模式包括平均電流、邊界導通、連續(xù)導通、臨界導通、電流控制式頻率折返、不連續(xù)和不連續(xù)導通，開關頻率從 6 kHz 至 1.7 MHz 可調(diào)。