www.fairchildsemi.com
REV. 1.0.12 9/24/03
Features
• TriFault Detect™ for UL1950 compliance and enhanced
safety
• Slew rate enhanced transconductance error amplifier for
ultra-fast PFC response
• Low power: 200µA startup current, 5.5mA operating
current
• Low total harmonic distortion, high PF
• Average current, continuous boost leading edge PFC
• Current fed gain modulator for improved noise immunity
• Overvoltage and brown-out protection, UVLO, and soft
start
• Synchronized clock output
General Description
The FAN4810 is a controller for power factor corrected,
switched mode power supplies. The FAN4810 includes
circuits for the implementation of leading edge, average
current, “boost” type power factor correction and results in a
power supply that fully complies with IEC1000-3-2 specifi-
cation. It also includes a TriFault Detect™ function to help
ensure that no unsafe conditions will result from single
component failure in the PFC. Gate-driver with 1A
capability minimizes the need for external driver circuit.
Low power requirements improve efficiency and reduce
component costs. The PFC also includes peak current
limiting, input voltage brownout protection and a over-
voltage comparator shuts down the PFC section in the event
of a sudden decrease in load. The clock-out signal can be
used to synchronize down-stream PWM stages in order to
reduce system noise.
Block Diagram
15
VEAO
IEAO
V
FB
I
AC
V
RMS
I
SENSE
RAMP 1
CLKSD
OSCILLATOR
OVP
PFC I
LIMIT
V
REF
POWER FACTOR CORRECTOR
TRI-FAULT
2.5V
+
–
–
+
16
2
4
3
7.5V
REFERENCE
14
V
CC
13
V
CC
VEA
7
-
+
IEA
1
+
–
+
–
+
–
PFC OUT
12
S
R
Q
Q
S
R
Q
Q
2.75V
0.5V
-1V
8
11
10
6
5
9
GAIN
MODULATOR
3.6kΩ
3.6kΩ
17V
UVLO
CLKOUT
S
R
Q
Q
V
CC
DUTY CYCLE
LIMIT
–
+
–
+
2.45V
V
FB
V
REF
V
IN
OK
V
CC
25µA
1.25V
FAN4810
Power Factor Correction Controller
