9
GLOBAL ENERGY EFFICIENCY SPECIALIST
Reverse polarity protection is recommended
under installation and cabling conditions where
reverse polarity across the input may occur.
V
in
(+)
V
in
(-)
V
in
(+)
V
in
(-)
The converter has no internal fuse. To
meet
safety and regulatory requirements, a 25 A fuse
is recommended.
Recommend Reverse Polarity
Protection Circuit
Figure 19: Recommend reverse polarity protection
circuits
Recommended Fuse
Input Undervoltage Protection
The converter will shut down after the input voltage
drops below the undervoltage protection threshold
for shutdown. The converter will start to work again
after the input voltage reaches the input
undervoltage protection threshold for startup. For
the Hysteresis, see the Protection characteristics.
Output Overcurrent Protection
The converter equipped with current limiting
circuitry can provide protection from an output
overload or short circuit condition. If the output
current exceeds the output overcurrent protection
threshold, the converter enters hiccup mode. When
the fault condition is removed, the converter will
automatically restart.
Output Overvoltage Protection
When the voltage directly across the output pins
exceeds the output overvoltage protection
threshold, the converter enters overvoltage
protection mode and the output voltage becomes
a constant one. When the fault condition is
removed, the output voltage will be normal.
Overtemperature Protection
A temperature sensor on the converter senses the
average temperature of the module. It protects the
converter from being damaged at high
temperatures. When the temperature exceeds the
overtemperature protection threshold, the output
will shut down. It will allow the converter to turn on
again when the temperature of the sensed location
falls by the value of overtemperature Protection
Hysteresis.
MTBF
The MTBF is calculated according to the
Telcordia, SR332 Method 1 Case3.
The fuse current should be 1.5 to 2 times the maximum
operating current in actual use.
GAQ37S12B-4
DC-DC Converter Technical Manual V1.0
