GE Industrial Solutions 6A Austin MicroLynx II - Manual (Page 12)

GE Energy
Data Sheet
6A Austin MicroLynx TM II: Non-Isolated DC-DC Power Modules
8.3Vdc –14Vdc input; 0.75Vdc to 5.5Vdc output; 6A Output Current
October 16, 2012 ©2012 General Electric Company. All rights reserved. Page 12
Feature Description
Remote On/Off
Austin MicroLynx TM II 12V SMT power modules feature an
On/Off pin for remote On/Off operation. Two On/Off logic
options are available in the Austin MicroLynx
TM II 12V series
modules. Positive Logic On/Off signal, device code suffix “4”,
turns the module ON during a logic High on the On/Off pin and
turns the module OFF during a logic Low. Negative logic
On/Off signal, no device code suffix, turns the module OFF
during logic High and turns the module ON during logic Low.
For positive logic modules, the circuit configuration for using
the On/Off pin is shown in Figure 28. The On/Off pin is an open
collector/drain logic input signal (Von/Off) that is referenced to
ground. During a logic-high (On/Off pin is pulled high internal
to the module) when the transistor Q1 is in the Off state, the
power module is ON. Maximum allowable leakage current of
the transistor when Von/off = V
IN,max
is 10µA. Applying a logic-
low when the transistor Q1 is turned-On, the power module is
OFF. During this state VOn/Off must be less than 0.3V. When
not using positive logic On/off pin, leave the pin unconnected
or tie to V
IN.
Figure 28. Circuit configuration for using positive logic
On/OFF.
For negative logic On/Off devices, the circuit configuration is
shown is Figure 29. The On/Off pin is pulled high with an
external pull-up resistor (typical R
pull-up
= 68k, +/- 5%). When
transistor Q1 is in the Off state, logic High is applied to the
On/Off pin and the power module is Off. The minimum On/off
voltage for logic High on the On/Off pin is 2.5 Vdc. To turn the
module ON, logic Low is applied to the On/Off pin by turning
ON Q1. When not using the negative logic On/Off, leave the
pin unconnected or tie to GND.
Figure 29. Circuit configuration for using negative logic
On/OFF.
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 2A.
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
ref2
,
(see Figure 33) exceeds 140 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 restarts after it cools down.
Q1
R2
R1
Q2
R3
R4
Q3 CSS
GND
VIN+
ON/OFF
PWM Enable
+
_
ON/OFF
V
I
ON/OFF
MODULE
Q1
R1
R2
Q2 CSS
GND
PWM Enable
ON/OFF
VIN+
ON/OFF
_
+
V
I
MODULE
pull-up
R
ON/OFF