GE Industrial Solutions Austin Lynx II SIP - Manual (Page 13)

Data Sheet
October 2, 2009 Austin Lynx TM II SIP Non-isolated Power Modules:
2.4 – 5.5Vdc input; 0.75Vdc to 3.63Vdc Output; 10A output current
LINEAGE POWER 13
Feature Descriptions (continued)
Output Voltage Programming
The output voltage of the Austin Lynx TM II SIP can be
programmed to any voltage from 0.75 Vdc to 3.3 Vdc by
connecting a single resistor (shown as Rtrim in Figure
31) between the TRIM and GND pins of the module.
Without an external resistor between the 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
For example, to program the output voltage of the
Austin Lynx
TM II module to 1.8 Vdc, Rtrim is calculated is
follows:
Ω −
−
= ⎥⎦
⎤
⎢⎣
⎡
5110
7525 . 0 8 . 1
21070
Rtrim
Ω = k Rtrim 004 . 15
V
O
(+)
TRIM
GND
R
trim
LOAD
V
IN
(+)
ON/OFF
Figure 31. Circuit configuration to program output
voltage using an external resistor.
Table 1 provides Rtrim values required for some
common output voltages.
Table 1
V
O,
(V) Rtrim (KΩ)
0.7525 Open
1.2 41.973
1.5 23.077
1.8 15.004
2.5 6.947
3.3 3.160
By a using 1% tolerance trim resistor, set point
tolerance of ±2% is achieved as specified in the
electrical specification. The POL Programming Tool,
available at
www.lineagepower.com under the Design
Tools section, helps determine the required external
trim resistor needed for a specific output voltage.
The amount of power delivered by the module is defined
as the voltage at the output terminals multiplied by the
output current. When using the trim feature, the output
voltage of the module can be increased, which at the
same output current would increase the power output of
the module. Care should be taken to ensure that the
maximum output power of the module remains at or
below the maximum rated power (P
max
= V
o,set
x I
o,max
).
Voltage Margining
Output voltage margining can be implemented in the
Austin Lynx
TM II SIP modules by connecting a resistor,
R
margin-up
, from the Trim pin to the ground pin for
margining-up the output voltage and by connecting a
resistor, R
margin-down
, from the Trim pin to the Output pin
for margining-down. Figure 32 shows the circuit
configuration for output voltage margining. The POL
Programming Tool, available at
www.lineagepower.com
under the Design Tools section, also calculates the
values of R
margin-up
and R
margin-down
for a specific output
voltage and % margin. Please consult your local
Lineage Power technical representative for additional
details.
Vo
Austin Lynx or
Lynx II Series
GND
Trim
Q1
Rtrim
Rmargin-up
Q2
Rmargin-down
Figure 32. Circuit Configuration for margining
Output voltage.
Feature Descriptions (continued)