Reverse polarity protection VN808SR
12/17 Doc ID 11624 Rev 5
6 Reverse polarity protection
This schematic can be used with any type of load.
The following is an indication on how to dimension the R
GND
resistor.
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 polarity situations) is:
PD = (-V
CC
)
2
/R
GND
Note: In normal condition (no reverse polarity) due to the diode there will be a voltage drop
between GND of the device and GND of the system.
Figure 8. Reverse polarity protection
Status
Input
i
GND
Output
i
+ Vcc
R
GND
Load
Diode
Status
Input
i
GND
Output
i
+ Vcc
R
GND
Load
Diode
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