E-L9823013TR Datasheet, PDF (14/19 Pages) STMicroelectronics – Octal low-side driver for bulb, resistive and inductive loads with serial input control, output protection and diagnostic

Functional description
L9823
3.3
Diagnostics
The output voltage at all outputs is compared with the diagnostic threshold, typ 0,55  V_DD =
V_DG.
Output
Table 7. Diagnostic for outputs
Output voltage
Status bit
Output mode
off
> DG-threshold
high
correct operation
off
< DG-threshold
low
fault condition 2)
on
< DG-threshold
low
correct operation
on
> DG-threshold
high
fault condition 1)
Fault condition 1
Output short circuit to Vbat:
 For SFPD = Low the output was switched on and the voltage at the output exceeded
the diagnostics threshold due to overcurrent, the output overload latch was set and the
output has been switched off. The diagnostic bit is high.
 For SFPD = high the output was switched on and the voltage at the output exceeds the
diagnostics threshold. The output operates in current regulation mode or has been
switched off due to thermal shutdown. The status bit is high.
Fault condition 2
Open load or output short circuit to GND:
 The output is switched off and the voltage at the output drops below the diagnostics
threshold, because the load current is lower than the output diagnostic current source,
the load is interrupted. The diagnostic bit is low.
 At the falling edge of CSB the output status data are transferred to the shift register.
When SCB is low, data bits contained in the shift register are transferred to SO output
at every rising SCLK edge.
Figure 5. Pulse diagram to read the outputs status register
#3"
3#,+
3)
3/
-3"       ,3"
-3"       ,3"
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DocID7791 Rev 7