GE Industrial Solutions KSTW015A0F Barracuda Series - Manual (Page 7)

GE Data Sheet
KSTW015A0F Barracuda™ Series; DC-DC Converter Power Modules
36-75Vdc Input; 3.3Vdc, 15A Output
April 1, 2013 ©2012 General Electric Company. All rights reserved. Page 7
Feature Description
Remote On/Off
Two remote on/off options are available. Positive logic turns
the module on during a logic high voltage on the on/off pin,
and off during a logic low. Negative logic remote on/off, device
code suffix “1”, turns the module off during a logic high and on
during a logic low.
ON/OFF
Vin+
Vin-
I
on/off
V
on/off
Vout+
TRIM
Vout-
Figure 10. Circuit configuration for using Remote On/Off
Implementation.
To turn the power module on and off, the user must supply a
switch (open collector or equivalent) to control the voltage
(V
on/off
) between the ON/OFF terminal and the V
IN
(-) terminal.
Logic low is 0V ≤ V
on/off
≤ 0.8V. The maximum I
on/off
during a
logic low is 0.15mA, the switch should be maintain a logic low
level whilst sinking this current.
During a logic high, the typical V
on/off
generated by the module
is 4.0V, and the maximum allowable leakage current at V
on/off
=
4.0V is 25μA.
If not using the remote on/off feature:
For positive logic, leave the ON/OFF pin open.
For negative logic, short the ON/OFF pin to V
IN
(-).
Overcurrent 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. If the unit
is not configured with auto–restart, then it will latch off
following the over current condition. The module can be
restarted by cycling the dc input power or by toggling the
remote on/off signal. If the unit is configured with the auto-
restart option (4), it will remain in the hiccup mode as long as
the overcurrent condition exists; it operates normally, once the
output current is brought back into its specified range.
Overtemperature Protection
To provide protection under certain fault conditions, the unit is
equipped with a thermal shutdown circuit. The unit will shut
down if the thermal reference point Tref (Figure 16), exceeds
135 o C (typical), but the thermal shutdown is not intended as a
guarantee that the unit will survive temperatures beyond its
rating. The module will automatically restart upon cool-down
to a safe temperature.
Input Undervoltage Lockout
At input voltages below the input undervoltage lockout limit,
the module operation is disabled. The module will only begin to
operate once the input voltage is raised above the
undervoltage lockout turn-on threshold, V
UV/ON
.
Once operating, the module will continue to operate until the
input voltage is taken below the undervoltage turn-off
threshold, V
UV/OFF
.
Over Voltage Protection
The output overvoltage protection shall consist of circuitry that
independently monitors the output voltage, and shuts the
module down if the output voltage exceeds specified limits.
This protection feature latches in the event of over voltage
across the output. Cycling the on/off pin or input voltage resets
the latching protection feature. If the auto-restart option (4) is
ordered, the module will automatically restart upon an
internally programmed time elapsing.
Output Voltage Programming
Trimming allows the user to increase or decrease the output
voltage set point of the module. This is accomplished by
connecting an external resistor between the TRIM pin and
either the Vout+ pin or the Vout- pin.
Trim Down – Decrease Output Voltage
By connecting an external resistor (Radj-down) between the
TRIM pin and V
O
(-) or SENSE(-) pin (see figure 11), the output
voltage set point decreases. The following equation
determines the external resistor value to obtain an output
voltage change from V
o,set
to the desired V
o,desired
:









k R
down adj
22 . 10
%
511
Where 100 %
,
, , 







 
 
set o
desired o set o
V
V V
Figure 11. Circuit Configuration to Decrease Output Voltage.
Trim Up – Increase Output Voltage
By connecting an external resistor (Radj-up) between the TRIM
pin and V
O
(+) or SENSE(+) pin (see figure 12), the output voltage
set point increases. The following equation determines the
external resistor value to obtain an output voltage change
from V
o,set
to the desired V
o,desired
: