Data Sheet
Austin LynxTM 24V: Non-isolated Power Modules:
June 16, 2009
18/20– 30Vdc input; 3.0 – 6.0Vdc & 5.0 – 15.0Vdc Output; 30& 50W
Feature Description
Rdistribution Rcontact
Rcontact Rdistribution
VIN(+)
VO
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.
Sense
RLO AD
Rdistribution Rcontact
Rcontact Rdistribution
COM
CO M
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 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
.
VIN+
MODULE
R2
Input Undervoltage Lockout
ON/OFF
Q2
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.
+
R1
V
ON/OFF
I
ON/OFF
PWM Enable
R3
R4
Overtemperature Protection
Q1
Q3
CSS
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.
GND
_
Figure 28. Remote On/Off Implementation circuit.
Remote Sense
Output Voltage Programming
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 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:
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.
For the AX030A0X modules,
10500
⎡
⎤
Rtrim =
− 3480 Ω
⎢
⎣
⎥
⎦
Vo − 3.018
LINEAGE POWER
11
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
