BTS7040-1EPA
PROFET™ +2 12V
Diagnosis
9.3.1
Open Load current (IIS(OLOFF))
In OFF state, when DEN pin is set to “high”, the VDS voltage is compared with a threshold voltage VDS(OLOFF). If
the load is properly connected and there is no short circuit to battery, VDS ~ VS therefore VDS > VDS(OLOFF). When
the diagnosis is active and VDS ≤ VDS(OLOFF), a current IIS(OLOFF) is provided by IS pin. Figure 38 shows the
relationship between IIS(OLOFF) and IIS(FAULT) as functions of VDS. The two currents do not overlap making it always
possible to differentiate between Open Load in OFF and Fault condition.
IIS
IIS(FAULT)
IIS(OLOFF)
VDS(OLOFF)
VDS
Figure 38 IIS in OFF State
It is necessary to wait a time tIS(OLOFF)_D between the falling edge of the input pin and the sensing at pin IS for
Open Load in OFF diagnosis to allow the internal comparator to settle. In Figure 39 the timings for an Open
Load detection are shown - the load is always disconnected.
IN
t
DEN
tIS(OLOFF)_D
t
VOUT
VDS(OLOFF)
~ VS
Load
conn ect ed
t
t
IIS
IIS(OLOFF)
IIS(OL)
Diagnosis_PROFET_OLOFF_time.emf
Figure 39 Open Load in OFF Timings - load disconnected
Data Sheet
47
Rev. 1.10
2020-12-14
INFINEON [ Infineon ]
