描述 Description

The FAN4800 is a controller for power-factor-corrected, switched-mode power supplies. Power Factor Correction (PFC) allows the use of smaller, lower-cost bulk capacitors, reduces power line loading and stress on the switching FETs, and results in a power supply that fully complies with IEC-1000-3-2 specifications. Intended as a BiCMOS version of the industry-standard ML4800, the

FAN4800 includes circuits for the implementation of leading edge, average current, boost-type power factor correction, and a trailing-edge Pulse Width Modulator (PWM). A gate driver with 1A capabilities minimizes the need for external driver circuits. Low-power require ments improve efficiency and reduce component costs.

特性 Features

?Low start-up current (100μA typical)

?Low operating current (2.5mA typical)

?Low total harmonic distortion, high power factor

?Pin-compatible upgrade for the ML4800

?Average current, continuousor discontinuous boost, leading-edge PFC

?Slew rate enhanced transconductance error amplifier for ultra-fast PFC response

?Internally synchronized leading edge PFC and trailing edge PWM

?Reduction of ripple current in the storage capacitor between the PFC and PWM sections

?PWM configurable for current-mode or voltage-mode operation

?Additional folded-back current limit for PWM section

?20V BiCMOS process

?VINOK guaranteed turn-on PWM at 2.25V

?VCCOVP comparator, low-power detect comparator

?Current-fed gain modulator for improved noise immunity

?Brownout control, over-voltage protection, UVLO, soft-start, and reference OK

?Available in 16-DIP, 16-SOIC (wide) packages

Applications

?Desktop PC Power Supply

?Internet Server Power Supply

?Uninterruptible Power Supply (UPS)

?Battery Charger

?DC Motor Power Supply

?Monitor Power Supply

?Telecom System Power Supply

?Distributed Power