FAN4800I Fairchild Semiconductor, FAN4800I Datasheet - Page 2

• Manufacturer Part Number: FAN4800I
• Description: The FAN4800 is a controller for power-factor-corrected, switched-mode power supplies
• Manufacturer: Fairchild Semiconductor

FAN4800 Rev. 1.0.6
© 2005 Fairchild Semiconductor Corporation
Block Diagram
15
2
4
3
7
8
6
5
9
V
V
DC I
I
RAMP2
V
SS
2.5V
RAMP1
I
AC
RMS
SENSE
FB
DC
V
LIMIT
CC
V
20μA
0.9V
REF
V
EAO
350
MODULATOR
350
GAIN
16
0.3V
3.5k
3.5k
Low Power
Detector
I
EAO
PWM CMP
Figure 1. Internal Block Diagram
SS CMP
PULSE WIDTH MODULATOR
1
17.9V
PFC CMP
OSCILLATOR
V
0.5V
CC
2.25V
POWER FACTOR CORRECTOR
V
TRI-FAULT
FB
2
V
V
IN
CC
OK
OVP
DUTY CYCLE
2.78V
LIMIT
1.0V
-1V
DC I
Q
PFC OVP
LIMIT
PFC I
PWM DUTY
S
R
LIMIT
V
CC
REFERENCE
UVLO
S
R
S
R
S
R
7.5V
13
Q
Q
Q
V
CC
FAN4800 Rev.02
OUT
OUT
PWM OUT
PFC
PWM
CLK
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PFC OUT
GND
V
REF
14
12
11
10