GE Industrial Solutions 12V AustinLynx 10A - Manual (Page 12)

GE
Data Sheet
12V AustinLynx TM 10A: Non-Isolated DC-DC Power Modules,Programmable
10Vdc –14Vdc input; 0.75Vdc to 5.5Vdc output; 10A Output Current
May 8, 2013 ©2013 General Electric Company. All rights reserved. Page 12
Feature Description
Remote On/Off
The 12V Austin Lynx Programmable SMT power modules
feature an On/Off pin for remote On/Off operation. If not using
the remote On/Off pin, leave the pin open (module will be On).
The On/Off pin signal (Von/Off) is referenced to ground. To
switch the module on and off using remote On/Off, connect an
open collector npn transistor between the On/Off pin and the
ground pin (See Figure 27).
During a logic-high (On/Off pin is pulled high internal to the
module) when the transistor is in the Off state, the power
module is ON. The maximum allowable leakage current of the
transistor when Von/off = V
IN,max
is 10µA. During a logic-low
when the transistor is turned-on, the power module is OFF.
During this state VOn/Off is less than 0.3V and the maximum
IOn/Off = 1mA.
Q1
R2
R1
Q2
R3
R4
Q3 CSS
GND
VIN+
ON/OFF
PWM Enable
+
_
ON/OFF
V
I
ON/OFF
MODULE
Figure 27. Remote On/Off Implementation.
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. The unit
operates normally once the output current is brought back into
its specified range. The typical average output current during
hiccup is 3 A.
Input Undervoltage Lockout
At input voltages below the input undervoltage lockout limit,
module operation is disabled. The module will begin to operate
at an input voltage above the undervoltage lockout turn-on
threshold.
Overtemperature Protection
To provide over temperature protection in a fault condition, the
unit relies upon the thermal protection feature of the controller
IC. The unit will shutdown if the thermal reference point T
ref
,
exceeds 125 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 after it
cools down.
Output Voltage Programming
The output voltage of the 12V Austin Lynx Programmable SMT
module can be programmed to any voltage from 0.75Vdc to
5.5Vdc by connecting a resistor (shown as Rtrim in Figure 28)
between Trim and GND pins of the module. Without an
external resistor between Trim and GND pins, the output of the
module will be 0.7525Vdc. To calculate the value of the trim
resistor, Rtrim for a desired output voltage, use the following
equation:
Ω




−
−
= 1000
7525 . 0
10500
Vo
Rtrim
For example, to program the output voltage of the 12V Austin
Lynx Programmable SMT module to 1.8 Vdc, Rtrim is calculated
is follows:




−
−
= 1000
75 . 0 8 . 1
10500
Rtrim
Ω = k Rtrim 024 . 9
V
O
(+)
TRIM
GND
R
trim
LOAD
V
IN
(+)
ON/OFF
Vout
Figure 28. Circuit configuration for programming output
voltage using an external resistor.
Table 1 provides Rtrim values required for some common
output voltages
Table 1
V
O, set
(V) Rtrim (KΩ)
0.7525 Open
1.2 22.46
1.5 13.05
1.8 9.024
2.5 5.009
3.3 3.122
5.0 1.472