L6370 Circuit description
Doc ID 4282 Rev 8 9/18
3.1 Diagnostic truth table
3.2 Input section
The input section is an high impedance differential stage with high common and differential
mode range. There’s built-in offset of +1.4 V (typical value) and an hysteresis of 400 mV
(maximum value), to ensure high noise immunity.
3.3 Diagnostic logic
The operating conditions of the device are permanently monitored and the following
occurrences are signalled via the DIAG1/DIAG2 open-drain output pins:
– Short circuit versus ground. A current limiting circuit fixes at I
sc
= 3.2 A (typical
value) the maximum current that can be sourced from the OUTPUT pin (for more
details see short circuit operation section).
– Short circuit versus Vs.
– Under voltage (UV)
– Over temperature (OVT)
– Open load, if the output current is less than 3 mA (typical value).
– Output DMOS open according to the diagnostic truth Tab l e 7 .
Table 7. Diagnostic truth table
Diagnostic conditions Input Output Diag1 Diag2
Normal operation
L
H
L
H
H
H
H
H
Open load condition (I
o
< I
old
)
L
H
L
H
H
L
H
H
Short to V
S
L
H
H
H
L
L
H
H
Short circuit to ground (I
O
= I
SC
)
(1)
(pin ON-DELAY grounded)
1. A cold lamp filament, or a capacitive load may activate the current limiting circuit of the IPS, when the IPS
is initially turned on.
H
L
X
L
H
H
H
H
Output DMOS open
L
H
L
L
H
L
H
H
Overtemperature
L
H
L
L
H
H
L
L
Supply undervoltage (V
S
< V
sth2
)
L
H
L
L
L
L
L
L
