Application information VN5E050AJ-E
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3 Application information
Figure 32. Application schematic
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 can be used with any type of load.
The following show 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 amongst several different HSDs. Please note that the value of
this resistor should be 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, then the
R
GND
will produce a shift (I
S(on)max
* R
GND
) in the input thresholds and the status output
V
CC
GND
OUTPUT
D
GND
R
GND
D
ld
Μ
CU
+5V
V
GND
CS_DIS
IINPUT
R
prot
R
prot
CURRENT SENSE
R
prot
R
SENSE
C
ext
