ICLS6022J Datasheet, PDF (21/33 Pages) Infineon Technologies AG – LED System Driver ICs

LED System Driver ICs
ICLS6x Series
Functional Description
3.6
Control Unit
The Control Unit contains the functions for the Auto Restart and Floating Load Protection (FLP) modes. The Auto
Restart mode is combined with an adjustable blanking window, which varies according to the value of the external
soft start capacitor. The IC avoids entering into either of these two modes accidentally by means of this adjustable
blanking window. The window also provides a certain time during which overload detection is delayed. This delay
is useful for applications that normally work with a low current and occasionally require a short duration of high
current.
3.6.1 Adjustable Blanking Window
V_SoftS swings between 3.2 V and 3.6 V after the LED drive has settled and S2 is on while S3 is off. This behavior
is due to the frequency jittering function that makes use of the soft start pin. If overload occurs, V_FB exceeds 4.5 V.
The Auto Restart mode cannot be entered as the gate G5 is still blocked by the comparator C3. However, after
V_FB has exceeded 4.5 V, the switch S2 is opened and S3 is closed. The external soft start capacitor can then be
further charged by the integrated pull-up resistor R_SoftS through the switch S3. The comparator C3 releases the
gate G5 once V_SoftS has exceeded 4.0 V. This means that Auto Restart mode cannot be entered during the
charging time of the external capacitor C_SoftS.
SoftS
3. 0V
S1
5V
S3
RSoftS
Frequency
S2
Jitter
C3
4.0V
4.5V
C4
FB
Figure 15 Adjustable blanking window
&
Auto
G5
Restart
Mode
Control Unit
Data Sheet
21
Version 1.0, 2011-05-19