VND5025LAK-E Application information
Doc ID 12794 Rev 6 21/31
3 Application information
Figure 26. Application schematic
(1)
1. Channel 2 has the same internal circuit as channel 1
3.1 GND protection network against reverse battery
This section provides two solutions for implementing a ground protection network against
reverse battery.
3.1.1 Solution 1: Resistor in the ground line (R
GND
only)
This first solution can be used with any type of load.
The following formulas indicate how to dimension the R
GND
resistor:
1. R
GND
≤ 600mV / (I
S(on)max
)
2. R
GND
≥ (-V
CC
) / (-I
GND
)
where -I
GND
is the DC reverse ground pin current and can be found in the absolute
maximum rating section of the device datasheet.
Power Dissipation in R
GND
(when V
CC
< 0 during reverse battery situations) is:
P
D
=(-V
CC
)
2
/R
GND
This resistor can be shared among several different HSDs. Please note that the value of this
resistor is calculated with formula (1), where I
S(on)max
becomes the sum of the maximum on-
state currents of the different devices.
Please note that if the microprocessor ground is not shared by the device ground, the R
GND
produces a shift (I
S(on)max
* R
GND
) in the input thresholds and the status output values. This
shift varies depending on how many devices are ON in the case of several high-side drivers
sharing the same R
GND
.
V
CC
GND
OUTPUT
D
GND
R
GND
D
ld
µC
+5V
V
GND
CS_DIS
R
prot
R
prot
CURRENT SENSE
R
prot
R
SENSE
C
EXT
INPUT
