ILD4071 Datasheet, PDF (16/25 Pages) Infineon Technologies AG – LED Driver for High Power LEDs

ILD4071
Enable, Dimming Function and Thermal Protection
6.3
Overtemperature Protection of the Device
A temperature sensor at the power stage causes the overheated device to switch OFF to prevent destruction.
During over temperature condition the internal ST transistor is switched OFF. Due to the autorestart function of
the device the status signal will toggle accordingly. The timing of this pattern is dependant on the thermal capability
of the application and can be used to distinguish between open load error and overtemperature condition. More
details on the overtemperature behavior is displayed in Figure 7 below.
V_EN
H
L
t
T_j
T_jSD
ΔΤ
T_jSO
Ta
t
V_SW
t
I_LED
I_peak
t
ST
t
ST pull-
down OFF
ST pull-down transistor ON
ST
ST
ST
ST
ST
ST
ST
OFF
ON
OFF
ON
OFF
ON
OFF
Figure 7 Overtemperature Behavior
Datasheet
16
Rev. 1.0, 2011-11-16