L4981B

L4981A ® L4981B POWER FACTOR CORRECTOR 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 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 con- BLOCK DIAGRAM MULTIPOWER BCD TECHNOLOGY DIP20 SO20 ORDERING NUMBERS: L4981X (DIP20) L4981XD (SO20) trol functions for designing a high efficiency-mode power supply with sinusoidal line current consumption. 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- November 2001 1/16 L4981A - L4981B put filter; both the operating frequency modes working with an average current mode PWM controller, maintaining sinusoidal line current without slope compensation. Besides power MOSFET gate driver, precise voltage reference (externally available), error amplifier, undervoltage lockout, current sense and the soft start are...