ICE1QS01 Datasheet, PDF (10/21 Pages) Infineon Technologies AG – Controller for Switch Mode Power Supplies Supporting Low Power Standby and Power Factor Correction (PFC)

ICE1QS01
Primary regulation
Primary regulation is achieved by activating the internal current sink. The current sink is connected
between pin SRC and ground. If V_RZI exceeds the 5V threshold the current sink is switched on. It is
switched off when V_RZI falls below 5V. The current sink discharges the C_SRC capacitor. C_SRC is
charged via the internal 20k resistor. If V_RZI exceeds the 4.4V threshold a flip-flop is set and the
resistor is switched off when V_RZI falls below 50 mV. The resistor is switched on again with the fall-
ing slope of gate drive OUT.
Diagram Primary Regulation
zero current counter = 0010
VRZI
5V
4.5V
OUT
20K
resistor
on
off
current
sink
on
off
VSRC
OUT
start R Q
stop S Q
0.05 V +
-
4.5 V +
RZI
-
+
5V ^-
RQ
SQ
ICE1QS01
RQ
SQ
5V
20k
SRC
current
sink
t
Version 1.4
10
27 Apr 2004