GE Industrial Solutions Austin Minilynx SMT - Manual (Page 12)

Data Sheet
September 10, 2013 Austin MiniLynx TM SMT Non-isolated Power Modules:
2.4 – 5.5Vdc input; 0.75Vdc to 3.63Vdc Output; 3A output current
LINEAGE POWER 12
Feature Description
Remote On/Off
The Austin MiniLynx TM SMT power modules feature
an On/Off pin for remote On/Off operation. Two
On/Off logic options are available in the Austin
MiniLynx
TM 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 on the On/Off pin 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 30. 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.
Q1
R2
R1
Q2
R3
R4
Q3 CSS
GND
VIN+
ON/OFF
PWM Enable
+
_
ON/OFF
V
I
ON/OFF
MODULE
Figure 30. Circuit configuration for using positive
logic On/OFF.
For negative logic On/Off devices, the circuit
configuration is shown is Figure 31. The On/Off pin is
pulled high with an external pull-up resistor (typical
R
pull-up
= 5k, +/- 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 1.5Vdc. 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.
Q1
R1
R2
Q2 CSS
GND
PWM Enable
ON/OFF
VIN+
ON/OFF
_
+
V
I
MODULE
pull-up
R
ON/OFF
Figure 31. 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
ref
,
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 restart after it cools down.
Output Voltage Programming
The output voltage of the Austin MiniLynx TM SMT can
be programmed to any voltage from 0.75 Vdc to 3.63
Vdc by connecting a single resistor (shown as Rtrim
in Figure 32) between the TRIM and GND pins of the
module. Without an external resistor between TRIM
pin and the ground, the output voltage of the module
is 0.7525 Vdc. To calculate the value of the resistor
Rtrim for a particular output voltage Vo, use the
following equation:
Ω




−
−
= 5110
7525 . 0
21070
Vo
Rtrim