Application information VNQ5E250AJ-E
24/37 Doc ID 17360 Rev 3
3 Application information
Figure 32. Application schematic
Note: Channel 2, 3, 4 have 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 can be used with any type of load.
The following is an indication on 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
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
Μ
CU
+5V
V
GND
CS_DIS
IINPUT
R
prot
R
prot
CURRENT SENSE
R
prot
R
SENSE
C
ext
