Datasheet

VN5E160AS-E Application information
Doc ID 15609 Rev 4 27/37
3.4.1 Short to V
CC
and OFF-state open load detection
Short to V
CC
A short-circuit between V
CC
and output is indicated by the relevant current sense pin set to
V
SENSEH
during the device OFF-state. Small or no current is delivered by the current sense
during the ON-state depending on the nature of the short-circuit.
OFF-state open-load with external circuitry
Detection of an open-load in off-mode requires an external pull-up resistor R
PU
connecting
the output to a positive supply voltage V
PU
.
It is preferable V
PU
to be switched-off during the module standby-mode in order to avoid the
overall standby current consumption to increase in normal conditions, i.e. when load is
connected.
An external pull-down resistor R
PD
connected between output and GND is mandatory to
avoid misdetection in case of floating outputs in OFF-state (see Figure 33: Current sense
and diagnostic).
R
PD
must be selected in order to ensure V
OUT
< V
OLmin
unless pulled up by the external
circuitry:
Equation 3
R
PD
≤ 22 K Ω is recommended.
For proper open load detection in OFF-state, the external pull-up resistor must be selected
according to the following formula:
Equation 4
For the values of V
OLmin
,V
OLmax
, I
L(off2)r
and I
L(off2)f
(see Table 10: Openload detection (8 V
< V
CC
< 18 V).
VVIRV
minOLf)off(LPD
OFF_upPull
OUT
2
2
=<⋅=
−
()
(
)
()
VV
RR
IRRVR
V
maxOL
PDPU
r)off(LPDPUPUPD
ON_upPull
OUT
4
2
=>
+
⋅⋅−⋅
=
−