GE Industrial Solutions Austin MegaLynx - Manual (Page 13)

Data Sheet
April 19, 2011 Austin MegaLynx TM Non-Isolated dc-dc Power Modules:
4.5 – 5.5Vdc input; 0.8 – 3.63Vdc output; 30A output current
6.0 – 14Vdc input; 0.8 – 5.5Vdc output; 25A output current
LINEAGE POWER 13
Safety Considerations
For safety agency approval the power module must be
installed in compliance with the spacing and separation
requirements of the end-use safety agency standards,
i.e., UL 60950, CSA C22.2 No. 60950-00, EN60950
(VDE 0850) (IEC60950, 3
rd edition) Licensed.
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements. The power module
has extra-low voltage (ELV) outputs when all inputs are
ELV.
Feature Descriptions
Remote On/Off
The Austin MegaLynx power modules feature a On/Off
pin for remote On/Off operation. If not using the On/Off
pin, connect the pin to ground (the module will be ON).
The On/Off signal (V
on/off
) is referenced to ground. Circuit
configuration for remote On/Off operation of the module
using the On/Off pin is shown in Figure 43.
During a Logic High on the On/Off pin (transistor Q1 is
OFF), the module remains OFF. The external resistor R1
should be chosen to maintain 3.0V minimum on the
On/Off pin to ensure that the module is OFF when
transistor Q1 is in the OFF state. Suitable values for R1
are 4.7K for input voltage of 12V and 3K for 5Vin. During
Logic-Low when Q1 is turned ON, the module is turned
ON.
Q1
GND
PWM Enable
ON/OFF
VIN+
ON/OFF
_
+
V
I
MODULE
R1
ON/OFF
100K
Thermal SD
1K
10K
Figure 43. Remote On/Off Implementation using
ON/OFF.
The On/Off pin can also be used to synchronize the
output voltage start-up and shutdown of multiple
modules in parallel. By connecting together the On/Off
pins of multiple modules, the output start-up can be
synchronized (please refer to characterization curves).
When On/Off pins are connected together, all modules
will shut down if any one of the modules gets disabled
due to undervoltage lockout or over temperature
protection.
Remote Sense
The Austin MegaLynx SIP power modules have a
remote sense feature to minimize the effects of
distribution losses by regulating the voltage at the
remote sense pin (See Figure 44). The voltage between
the Sense pin and the Vo pin must not exceed 0.5V.
The amount of power delivered by the module is defined
as the output voltage multiplied by the output current (Vo
x Io). When using Remote Sense, the output voltage of
the module can increase, which if the same output is
maintained, increases the power output from the module.
Make sure that the maximum output power of the
module remains at or below the maximum rated power.
When the Remote Sense feature is not being used,
connect the Remote Sense pin to output of the module.
V O
C O M
V IN (+ )
C O M
R L O A D
R
contact
R
distribution
R contact R distribution R contact
R
contact
R
distribution
R distribution
S ense
Figure 44. Effective Circuit Configuration for Remote
Sense operation.
Over Current Protection
To provide protection in a fault (output overload)
condition, the unit is equipped with internal
current-limiting circuitry and can endure current limiting
continuously. At the point of current-limit inception, the
unit enters hiccup mode. The unit operates normally
once the output current is brought back into its specified
range. The average output current during hiccup is 20%
I
O, max
.
Over Temperature Protection
To provide protection in a fault condition, the unit is
equipped with a thermal shutdown circuit. The unit will
shutdown if the overtemperature threshold of 130
o C is
exceeded at the thermal reference point T
ref
. The
thermal shutdown is not intended as a guarantee that the
unit will survive temperatures beyond its rating. Once
the unit goes into thermal shutdown it will then wait to
cool before attempting to restart.