ILD4071 Datasheet, PDF (18/25 Pages) Infineon Technologies AG – LED Driver for High Power LEDs

ILD4071
Open Load Diagnosis
7.3
Open Load Diagnosis
The ST pin can be connected directly to a µC input. During an open load condition the ST transistor is OFF. An
external pull up resistor connected to V_DD is required to signal a logic high signal on the ST pin during an open
load error. Please consider that this diagnosis functionality is only active if the device is in active mode (HIGH
potential at the EN pin).
Refer to application drawing Figure 13.
V_EN
High
Low
VPWMI
V_PWMI,OFF
V_PWMI,ON
VSW
SW - OFF
T_PWMI
SW - ON
SW - OFF
Open Load
Event
ST
t
SW - ON
SW - OFF
t
High - z
t
Open Load
t
tOL
Figure 8
ST pull-down transistor ON
Open Load diagnosis via µC connected to ST pin
ST pull-down transistor OFF ^t
Datasheet
18
Rev. 1.0, 2011-11-16