Figure 7-10 Fault reaction with RETRY
setting (shown for OCP occurrence on high-side when OUT is shorted to
ground)
Short occurrence and recovery scenario
with RETRY setting:
t1: An external short
occurs.
t2: OCP (Over Current
Protection) fault confirmed after tOCP, output disabled, nFAULT
asserted low to indicate fault.
t3: Device automatically
attempts retry (auto retry) after tRETRY. Each time output is
briefly turned on to confirm short occurrence and then immediately disabled
after tOCP. nFAULT remains asserted low through out. Cycle
repeats till driver is disabled by the user or external short is removed, as
illustrated further. Note that, in case of a TSD (Thermal Shut Down) event,
automatic retry time depends on the cool off based on thermal
hysteresis.
t4: The external short is
removed.
t5: Device attempts auto
retry. But this time, no fault occurs and device continues to keep the
output enabled.
t6: After a fault free
operation for a period of tCLEAR is confirmed, nFAULT is
de-asserted.
SPI variant only – Fault
status remains latched till a CLR_FLT command is issued.
Note that, in the event of an output
short to ground causing the high-side OCP fault detection, IPROPI pin will continue
to be pulled up to VIPROPI_LIM voltage to indicate this type of short,
while the output is disabled. This is especially useful for the HW (H) variant to
differentiate the indication of a short to ground fault from the other faults.