24V Austin LynxTM: Non-Isolated DC-DC Power Modules
20Vdc –30Vdc input; 5Vdc to 15Vdc output; 70W Output Power
©2016 General Electric Company. All rights reserved.
Feature Description
Remote On/Off
The Austin LynxTM 24V SMT power modules feature an On/Off
pin for remote On/Off operation. 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.
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 = VIN,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 1.2V. When not
using positive logic On/off pin, leave the pin unconnected or tie
to VIN.
Figure 28. Remote On/Off Implementation circuit.
Remote Sense
The Austin Lynx 24V 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 29).
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 increases the power output of 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 the
output of the module.
Figure 29. Effective Circuit Configuration for Remote
Sense operation.
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 average output current during hiccup is 20%
IO, max.
Input Undervoltage 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.
Overtemperature 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 130oC is exceeded at the thermal
reference point Tref . 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.
Output Voltage Programming
The output voltage of the Austin Lynx 24V can be programmed to
any voltage in the specified ranges by connecting a resistor
(shown as Rtrim in Figure 30) between the Trim and GND pins of
the module. Without an external resistor between the Trim and
GND pins, the output of the module will be at the low-end of the
specified range. To calculate the value of the trim resistor, Rtrim
for a desired output voltage, use the following equations: