Datasheet

Data Sheet 27 Rev. 2.1, 2011-09-01
PROFET™+ 12V
BTS5045-2EKA
Diagnostic Functions
7 Diagnostic Functions
For diagnosis purpose, the BTS5045-2EKA provides a combination of digital and analog signals at pin IS. These
signals are called SENSE. In case the diagnostic is disabled via DEN, pin IS becomes high impedance. In case
DEN is activated, the SENSE of the channel X is enabled/disabled via associated pin DSEL. Table 7 gives the
truth table.
7.1 IS Pin
The BTS5045-2EKA provides a SENSE current written I
IS
at pin IS. As long as no “hard” failure mode occurs (short
circuit to GND / current limitation / overtemperature / excessive dynamic temperature increase or open load at
OFF) a proportional signal to the load current (ratio
k
ILIS
= I
L
/ I
IS
) is provided. The complete IS pin and diagnostic
mechanism is described on Figure 20. The accuracy of the SENSE depends on temperature and load current.
The IS pin multiplexes the current
I
IS(0)
and I
IS(1)
, via the pin DSEL. Thanks to this multiplexing, the matching
between
k
ILISCHANNEL0
and k
ILISCHANNEL1
is optimized. Due to the ESD protection, in connection to V
S
, it is not
recommended to share the IS pin with other devices if these devices are using another battery feed. The
consequence is that the unsupplied device would be fed via the IS pin of the supplied device.
Figure 20 Diagnostic Block Diagram
Table 7 Diagnostic Truth Table
DEN DSEL IS
0 don’t care Z
1 0 Sense output 0
I
IS(0)
1 1 Sense output 1 I
IS(1)
V
s
I
IS0
=
I
L0
/ k
ILIS
DEN
IS
0
1
DSEL
Sense schematic.svg
I
IS1
=
I
L1
/ k
ILIS
1
0
Z
IS(AZ)
I
IS(FAULT)
FAULT