Datasheet

Application information VN5E010AH
26/37 Doc ID 15984 Rev 3
3.3.1 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 2
R
PD
22 kis recommended.
For proper open load detection in OFF-state, the external pull-up resistor must be selected
according to the following formula:
Equation 3
For the values of V
OLmin
,V
OLmax
, I
L(off2)r
and I
L(off2)f
(see Table 10: Open load detection (8 V
< VCC < 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







