VND5012AK-E
Figure 7. Application Schematic
+5V
V
CC
R
prot
CS_DIS
D
ld
R
prot
µC
INPUT
OUTPUT
R
prot
CURRENT SENSE
GND
R
SENSE
R
GND
V
GND
D
GND
Note: Channel 2 has the same internal circuit as channel 1.
A resistor (R
GND
=1kΩ) should be inserted in parallel to
GND PROTECTION NETWORK AGAINST
REVERSE BATTERY
GND
D
if the device drives an inductive load.
This small signal diode can be safely shared amongst
several different HSDs. Also in this case, the presence of
the ground network will produce a shift (j600mV) in the
input threshold and in the status output values if the
microprocessor ground is not common to the device
ground. This shift will not vary if more than one HSD
shares the same diode/resistor network.
Solution 1: Resistor in the ground line (R
can be used with any type of load.
only). This
GND
The following is an indication on how to dimension the
R
resistor.
GND
1) R
2) R
≤ 600mV / (I
).
S(on)max
)
GND
GND
GND
≥ (−V ) / (-I
CC
LOAD DUMP PROTECTION
where -I
is the DC reverse ground pin current and can
GND
be found in the absolute maximum rating section of the
D
is necessary (Voltage Transient Suppressor) if the
ld
device datasheet.
Power Dissipation in R
battery situations) is:
load dump peak voltage exceeds the V max DC rating.
CC
(when V <0: during reverse
CC
The same applies if the device is subject to transients on
the V
GND
line that are greater than the ones shown in the
CC
2
ISO T/R 7637/1 table.
P = (-V ) /R
D
CC
GND
This resistor can be shared amongst several different
HSDs. Please note that the value of this resistor should
µC I/Os PROTECTION:
If a ground protection network is used and negative
be calculated with formula (1) where I
becomes
S(on)max
transient are present on the V line, the control pins will
CC
the sum of the maximum on-state currents of the different
devices.
Please note that if the microprocessor ground is not
be pulled negative. ST suggests to insert a resistor (R
)
prot
in line to prevent the µC I/Os pins to latch-up.
The value of these resistors is a compromise between the
leakage current of µC and the current required by the
HSD I/Os (Input levels compatibility) with the latch-up
limit of µC I/Os.
shared by the device ground then the R
will produce a
GND
shift (I
* R
) in the input thresholds and the
GND
S(on)max
status output values. This shift will vary depending on
how many devices are ON in the case of several high side
-V
/I
≤ R
≤ (V
-V -V
OHµC IH GND
) / I
CCpeak latchup
prot
IHmax
drivers sharing the same R
.
GND
Calculation example:
If the calculated power dissipation leads to a large
resistor or several devices have to share the same
resistor then ST suggests to utilize Solution 2 (see
below).
For V
= - 100V and I
≥ 20mA; V
≥ 4.5V
CCpeak
latchup
OHµC
5kΩ ≤ R
≤ 65kΩ.
prot
Recommended R
value is 10kΩ.
prot
Solution 2: A diode (D
) in the ground line.
GND
8/13
STMICROELECTRONICS [ ST ]
