FAN4800_06 Datasheet, PDF (1/20 Pages) Fairchild Semiconductor – Low Start-Up Current PFC/PWM Controller Combos

November 2006
FAN4800
Low Start-Up Current PFC/PWM Controller Combos
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, continuous or 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
„ V_IN OK guaranteed turn-on PWM at 2.25V
„ V_CC OVP 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
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 capaci-
tors, 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.
An over-voltage comparator shuts down the PFC section
in the event of a sudden decrease in load. The PFC sec-
tion also includes peak current limiting and input voltage
brownout protection. The PWM section can be operated
in current or voltage mode, at up to 250kHz, and
includes an accurate 50% duty cycle limit to prevent
transformer saturation.
The FAN4800 includes a folded-back current limit for the
PWM section to provide short-circuit protection.
16-PDIP
16-SOIC
Ordering Information
Part Number
FAN4800IN
FAN4800IM
FAN4800IMX
Operating
Temp. Range
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
Pb-Free
Yes
Yes
Yes
Package
16-PDIP
16-SOIC
16-SOIC
Packing
Method
Rail
Rail
Tape & Reell
Marking
Code
FAN4800
FAN4800
FAN4800
© 2005 Fairchild Semiconductor Corporation
FAN4800 Rev. 1.0.5
www.fairchildsemi.com