l6375dtr STMicroelectronics, l6375dtr Datasheet - Page 9

• Manufacturer Part Number: l6375dtr
• Description: 0.5a Industrial Intelligent Power Switch
• Manufacturer: STMicroelectronics

L6375D
2.8
Over current operation
In order to implement a short circuit protection the output power MOS is driven in linear
mode to limit the output current to the I
to the Isc value) lasts for a Ton time interval, that can be set by means of a capacitor (C
connected to the ON DELAY pin according to the following formula:
T
for
50pF< C
After the T
interval with:
T
When also the Toff interval has expired, the out-put power MOS is switched ON. At this point
in time two conditions may occur
We call this unique feature Non Dissipative Short Circuit Protection and it ensures a very
safe operation even in permanent overload conditions. Note that choosing the most
appropriate value for the Ton interval (i.e. the value of the Cdon capacitor) a delay (the Ton
itself) will prevent that a misleading Short Circuit information is presented on the DIAG2
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 Ton = 0 but with the output current still
limited to Isc, and Diagnostic disabled) simply shorting to ground the the ON DELAY pin.
Figure 4.
on
off
= 1.28 µsec/pF
= 64 ·T
a)
b)
don
The overloadis still present, and then the output power MOS is again driven in
linear mode (limiting the output current to I
cycle, or
the over load the overload condition is removed, and the output power MOS is no
longer driven in linear mode. All these occurrences are presented on the DIAG2
pin (see fig 2).
on
on
< 2nF
Non dissipative short circuit protection operation
.
interval has expired the output power MOS is switched off for the T
sc
(1.1A typical value). This condition (current limited
SC
) for another T
Electrical specifications
ON
, starting a new
off
time
don
9/16
)