ICE1QS01 Datasheet, PDF (13/21 Pages) Infineon Technologies AG – Controller for Switch Mode Power Supplies Supporting Low Power Standby and Power Factor Correction (PFC)

ICE1QS01
Restart timer
If voltage V_RZI is lower than 50 mV and gate drive OUT is low an internally created restart pulse will
switch gate drive OUT high every 50 µs and the minimum switching frequency is about 20 kHz.
Restart pulse is inhibited if V_RZI is higher than 50 mV. So the MOS transistor cannot be switched on
until the transformer is discharged.
VCC overvoltage protection
If V_CC exceeds the V_CCD threshold a latch is set and the gate is disabled. Reset of latch occurs
when V_CC is falling below V_CCon- V_CCBHY.
Overvoltage fault comparator (OFC)
With an external sense resistor connected to pin OFC primary current can be sensed directly. If the
sensed current exceeds the internal V_OFC threshold a latch is set and gate is disabled. Reset of
latch occurs when V_CC is falling below V_CCon- V_CCBHY.
Notice: If this comparator is not used pin OFC has to be connected to ground.
Mains undervoltage
Power supplies must be shut down when mains voltage is below a certain limit to avoid too long on-
time of MOS-FET switch, which would lead to a switching frequency in audible spheres. Mains und-
ervoltage is sensed during the off-time of the MOS-FET switch. If the current flowing into pin PCS is
smaller than 100 uA, then the output is latched and cannot be switched to high state.
Diagram Mains Undervoltage Lockout Current
130
120
Ipcs/µA
110
100
90
80
70
60
50
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Temp./°C
Version 1.4
13
27 Apr 2004