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
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 ...