BTT6100-2EKA Datasheet, PDF (30/48 Pages) Infineon Technologies AG – Suitable for resistive, inductive and capacitive loads

7.3.3 SENSE Signal in Open Load
BTT6100-2EKA
Diagnostic Functions
7.3.3.1 Open Load in ON Diagnostic
If the channel is ON, a leakage current can still flow through an open load, for example due to humidity. The
parameter I_L(OL) gives the threshold of recognition for this leakage current. If the current I_L flowing out the power
DMOS is below this value, the device recognizes a failure, if the DEN (and DSEL) is selected. In that case, the
SENSE current is below I_IS(OL). Otherwise, the minimum SENSE current is given above parameter I_IS(OL).
Figure 23 shows the SENSE current behavior in this area. The red curve shows a typical product curve. The blue
curve shows the ideal current sense.
I_IS
I_IS(OL)
Figure 23 Current Sense Ratio for Low Currents
I_L(OL)
I_L
Sense for OL .vsd
7.3.3.2 Open Load in OFF Diagnostic
For open load diagnosis in OFF-state, an external output pull-up resistor (R_OL) is recommended. For the
calculation of pull-up resistor value, the leakage currents and the open load threshold voltage V_OL(OFF) have to be
taken into account. Figure 24 gives a sketch of the situation. I_leakage defines the leakage current in the complete
system, including I_L(OFF) (see Chapter 5.5) and external leakages, e.g, due to humidity, corrosion, etc... in the
application.
To reduce the stand-by current of the system, an open load resistor switch S_OL is recommended. If the channel x
is OFF, the output is no longer pulled down by the load and V_OUT voltage rises to nearly V_S. This is recognized by
the device as an open load. The voltage threshold is given by V_OL(OFF). In that case, the SENSE signal is switched
to the I_IS(FAULT).
An additional R_PD resistor can be used to pull V_OUT to 0V. Otherwise, the OUT pin is floating. This resistor can be
used as well for short circuit to battery detection, see Chapter 7.3.4.
Data Sheet
PROFET™+ 24V
30
Rev. 1.0, 2014-08-20