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TLE75008-EMD_15 Datasheet, PDF (43/64 Pages) Infineon Technologies AG – SPI Driver for Enhanced Relay Control
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TLE75008-EMD
Diagnosis
9
Diagnosis
The SPI of TLE75008-EMD provides diagnosis information about the device and the load status. Each channel
diagnosis information is independent from other channels. An error condition on one channel has no influence on
the diagnostic of other channels in the device (unless configured to work in parallel, see Chapter 7.2 for more
details).
9.1
Over Load and Over Temperature
When either an Over Load or an Over Temperature occurs on one channel, the diagnosis bit ERRn is set
accordingly. As described in Chapter 8.1 and Chapter 8.2, the channel latches OFF and must be reactivated
setting corresponding HWCR_OCL.OUTn bit to “1”.
9.2
Output Status Monitor
The device compares each channel VDS with VDS(OL) and sets the corresponding DIAG_OSM.OUTn bits
accordingly. The bits are updated every time DIAG_OSM register is read.
• VDS < VDS(OL) → DIAG_OSM.OUTn = “1”
A diagnosis current IOL in parallel to the power switch can be enabled by programming the DIAG_IOL.OUTn bit,
which can be used for Open Load at OFF detection. Each channel has its dedicated diagnosis current source. If
the diagnosis current IOL is enabled or if the channel changes state (ON → OFF or OFF → ON) it is necessary to
wait a time tOSM for a reliable diagnosis. Enabling IOL current sources increases the current consumption of the
device. Even if an Open Load is detected, the channel is not latched OFF.
See Figure 20 for a timing overview (the values of DIAG_IOL.OUTn refer to a channel in normal operation
properly connected to the load).
INn
OUT.OUTn
t
Output voltage
comparator
0
x
1
x
0
tON + tOSM
tOFF + tOSM
t
SPI readout of
DIAG_OSM.OUTn
t
DIAG_OSM.OUTn
x
1
x
0
0
t
OutStatMon_timings.emf
Figure 20 Output Status Monitor timing
Output Status Monitor diagnostic is available when VS = VS(NOR) and VDD ≥ VDD(UV).
Due to the fact that Output Status Monitor checks the voltage level at the outputs in real time, for Open Load in
OFF diagnostic it is necessary to sychronize the reading of DIAG_OSM register with the OFF state of the
channels.
Figure 21 shows how Output Status Monitor is implemented at concept level.
Data Sheet
43
Rev. 1.1, 2015-09-25
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