ILD4071 Datasheet, PDF (17/25 Pages) Infineon Technologies AG – LED Driver for High Power LEDs

ILD4071
Open Load Diagnosis
7
Open Load Diagnosis
7.1
Description
The ILD4071 has an integrated open load during ON diagnosis. During normal operation the ST pin (open collector
output) is pulled to GND (internal transistor is ON). The open load detection is realized by monitoring the switching
behavior at the SW pin. During an open load event the integrated power stage at the SW pin will be statically turned
ON. If the output stage is turned ON for more than the open load diagnosis delay time (t_OL) an open load condition
is detected. An open load event will switch OFF the internal transistor. If a µC is connected to the ST pin an
external pull up resistor should be placed to achieve a logic HIGH level for the proper open load error signalling
reporting. For a timing diagram on the functionality of the open load diagnosis please refer to Figure 8.
7.2
Electrical Characteristics: Open Load Diagnosis
All parameters have been tested at 25°C, unless otherwise specified.
Electrical Characteristics: Open Load Diagnosis
V_REC = 24 V, T_j = -40 °C to +125 °C, all voltages with respect to ground (unless otherwise specified)
Pos. Parameter
Symbol
Limit Values
Unit Conditions
Min. Typ. Max.
7.2.1 Open Load diagnosis
t_OL
DelayTime
20
–
–
µs –
7.2.2 Voltage Drop over internal V_Drop,ST
–
ST transistor
0.3
–
V
I_ST=150mA
Datasheet
17
Rev. 1.0, 2011-11-16