Datasheet

Over current operation L6377
10/16
When also the t
OFF
interval has expired, the output power MOS is switched ON.
Now two conditions may occur
● the overload is still present. In this case the output power MOS is again driven in linear
mode (limiting the output current to I
sc
) for another t
ON
, starting a new cycle, or
● the overload condition is removed, and the output power MOS is no longer driven in
linear mode.
All these occurrences are presented on the DIAG pin (see fig 5). We call this unique feature
non dissipative short circuit protection and it ensures a very safe operation even in
permanent overload conditions. Note that, of course, choosing the most appropriate value
for the t
ON
interval (i.e. the value of the C
DON
capacitor) a delay (the t
ON
itself) will prevent
that a misleading Short Circuit information is presented on the DIAG output, when driving
capacitive loads (that acts like short circuit in the very beginning) or Incandescent Lamp (a
cold filament has a very low resistive value).
The non dissipative short circuit protection can be disabled (keeping t
ON
= 0 but with the
output current still limited to Isc, and Diagnostic disabled) simply shorting to ground the the
ON DELAY pin.