GE Industrial Solutions Austin MegaLynx SMT User Manual
Page 17
Data Sheet
September 10, 2013
Austin MegaLynx
TM
SMT: Non-Isolated DC-DC Power Modules:
4.5 – 5.5Vdc input; 0.8 to 3.63Vdc Output; 30A output current
6.0 – 14Vdc Input; 0.8Vdc to 3.63Vdc Output; 20/30A output
LINEAGE
POWER
17
62SRPHZ modules have a higher value resistor of
100K connected internally between the gate and
source of the internal FET used to control the PWM
Enable line.
The On/Off pin can also be used to synchronize the
output voltage start-up and shutdown of multiple
modules in parallel. By connecting 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 shutdown if any one of the modules
gets disabled due to undervoltage lockout or over
temperature protection
.
Figure 50. Remote On/Off Implementation
using ON/OFF .
Remote Sense
The Austin MegaLynx
TM
SMT 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 51). The voltage
between the Sense pin and 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 by 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
LO AD
R
c ontact
R
distribution
R
c ontact
R
distribution
R
contact
R
contact
R
distribution
R
distribution
S ense
Figure 51. 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 10% 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
125
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.
Input Under Voltage Lockout
At input voltages below the input undervoltage
lockout limit, the module operation is disabled. The
module will begin to operate at an input voltage
above the undervoltage lockout turn-on threshold.
Output Voltage Programming
The output voltage of the Austin MegaLynx
TM
can
be programmed to any voltage from 0.8dc to
3.63Vdc by connecting a resistor (shown as R
trim
in
Figure 52) between Trim and GND pins of the
module. Without an external resistor between Trim
and GND pins, the output of the module will be
0.8Vdc. To calculate the value of the trim resistor,
R
trim
for a desired output voltage, use the following
equation:
Ω
−
−
=
100
80
.
0
1200
Vo
R
trim
R
trim
is the external resistor in Ω
Q1
GND
PW M Enable
ON/OFF
VIN+
ON/OFF
_
+
V
I
MODULE
R1
ON/OFF
100K
Thermal SD
1K
10K