Document
PFC / PWM Combination IC FA5533/34
Features Features
•Critical mode Power Factor Correction and PWM are combined : suitable for smaller power supply •Internal start-up circuit with 500V rating and low frequency operation achieves 340mW input at no load when PFC stops. • Small Output Capacitance : Linearly reduced frequency for light load makes small ripple voltage. • PFC stops below half load ( only for FA5533 ) •Vcc rating 28V allows no series regulator for
PW M_ FB
LV
www.DataSheet4U.com
BlockDiagram Diagram Block
COMP
MUL
underdevelopment development under
PFC_ IS
ZCD
AC
LIGHT_ LOAD
ZCD
ERR
PFC_ FB
+
MUL
R TIMER R
1shot
Overvoltage detection
OVP LV
OVP
S
+ -
R
Q
RESTART UVLO PFC_ REG_ OK LIGHT_ LOAD
UVLO_ AC
PFC_ OUT
PFC section
UVLO_ AC
+
UVLO_ AC
LIGHT_ LOAD
UVLO_ VCC
VCC
START
off
+
LV
-
-
+
PFC_ REG_ OK
VH
Common section
REG_ PFC
on
-
AC detect
ACD
PW M_ REG_ OK
REG_ PW M
on
PWM section
PW M_ REG
Q VCO OSC FOSC
PW M_ DELAY
Dma PW M
T Q CLR 1shot
T
S R Q
auxiliary winding to clamp Vcc voltage. •Adjustable Soft Start time •Auto-Restart Over Load Protection •Auto-Restart Over-Voltage Protection for Vcc •Adjustable Start-up sequence for PFC and PWM: easy Full Load Start-up •Brown-Out below 70Vac and 70Vdc of PFC Output •16 pins package ( DIP/SO )
CS
VCC
PW M OVP
slope
+
RESTART UVLO PW M_ REG_ OK LV UVLO_ AC
PW M_ OUT
+ -
+ +
+
PW M
VCC
+
RESTART
PW M_ REG
UVLO
+
LIGHT_ LOAD
delay
GND
+ Overload
RESTART
LIGHT_ LOAD
PW M_ IS
Usage : Notebook PC, LCD Monitor, LCD-TV, Laser Beam Printer etc.
PFC / PWM Combination IC FA5533/34
ApplicationCircuit Circuit Application underdevelopment development under
www.DataSheet4U.com
PFCsection section PFC
PWM PW M section section
PFC / PWM Combination IC FA5533/34
TimingChart Chart((FA5533 FA5533)) Timing
Heavy Load → Light Load → Heavy Load
PFC Gate of PFC OUTPUT MOSFET (drive)
www.DataSheet4U.com
underdevelopment development under
Stop ( Power-OFF )
AC Line AC line voltage voltage
Start-up ( Power-ON )
AC Line AC line voltage voltage
PFC PFC output OUTPUT voltage voltage PW M Gate of PWM OUTPUT (drive) MOSFET
VCC pin Vcc voltage voltage
Vcc VCC pin voltage voltage
PFC Gate of OUTPUT PFC (drive) MOSFET
Gate of PFC OUTPUT PFC (drive) MOSFET PFC PFC output OUTPUT voltage voltage
0.5V
PWM Output DC voltage OUTPUT
Full load
PFC PFC output OUTPUT voltage voltage Heavy Load
Light load
70Vdc
Light Load
Full load
Heavy Load
CS pin CS pin voltage
0.5V →
PW M Gate of PWM
OUTPUT
(drive) MOSFET
Gate of PWM PW M MOSFET (drive)
OUTPUT
PWMOutput DC voltage OUTPUT
Output PWMvoltage DC OUTPUT 5m s
5ms
.