ST L4981BD

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 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 input 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 included. To limit the number of the external components, the device integrates protections as overvoltage and overcurrent. The overcurrent level can be programmed using a simple resistor for L4981A. For a better precision and for L4981B an external divider must be used.

• CONTROL BOOST PWM UP TO 0.99P.F.
• LIMIT LINE CURRENT DISTORTION TO <5% UNIVERSAL INPUT MAINS
• FEED FORWARD LINE AND LOAD REGULA-TION
• AVERAGE CURRENT MODE PWM FOR MINIMUM NOISE SENSITIVITY
• HIGH CURRENT BIPOLAR AND DMOS TO-TEM POLE OUTPUT
• LOW START-UP CURRENT (0.3mA TYP.)
• UNDER VOLTAGE LOCKOUT WITH HYS-TERESIS AND PROGRAMMABLE TURN ON THRESHOLD
• OVERVOLTAGE, OVERCURRENT PROTEC-TION
• PRECISE 2% ON CHIP REFERENCE EX-TERNALLY AVAILABLE
• SOFT START