Data Sheet
March 27, 2008
JBW050A Power Modules: dc-dc Converter;
36 to 75 Vdc Input, 5 Vdc Output; 50 W
The voltage between the V
O
(+) and V
O
(–) terminals
must not exceed the minimum value of the output over-
voltage protection. This limit includes any increase in
voltage due to remote-sense compensation and output
voltage set-point adjustment (trim). See Figure 12.
Although the output voltage can be increased by both
the remote sense and by the trim, the maximum
increase for the output voltage is not the sum of both.
The maximum increase is the larger of either the
remote sense or the trim. Consult the factory if you
need to increase the output voltage more than the
above limitation.
8-651m
Feature Descriptions
(continued)
Remote Sense
(continued)
SENSE(+)
SENSE(–)
V
I
(+)
SUPPLY
I
I
V
I
(–)
CONTACT
RESISTANCE
V
O
(–)
CONTACT AND
DISTRIBUTION LOSSES
V
O
(+)
I
O
LOAD
Figure 12. Effective Circuit Configuration for
Single-Module Remote-Sense Operation
Output Voltage Set-Point Adjustment (Trim)
Output voltage trim allows the user to increase or
decrease the output voltage set point of a module. This
is accomplished by connecting an external resistor
between the TRIM pin and either the SENSE(+) or
SENSE(–) pins. The trim resistor should be positioned
close to the module.
If not using the trim feature, leave the TRIM pin open.
With an external resistor between the TRIM and
SENSE(–) pins (R
adj-down
), the output voltage set point
(V
O, adj
) decreases (see Figure 13). The following equa-
tion determines the required external-resistor value to
obtain a percentage output voltage change of
Δ%.
100
R
adj-down
=
⎛
---------
–
2
⎞
kΩ
-
⎝ Δ%
⎠
The test results for this configuration are displayed in
Figure 14. This figure applies to all output voltages.
With an external resistor connected between the TRIM
and SENSE(+) pins (R
adj-up
), the output voltage set
point (V
O, adj
) increases (see Figure 15).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output voltage
change of
Δ%.
)
V
O
(
100 +
Δ%
-
(
100 + 2Δ%
)
-
R
adj-up
=
⎛
-------------------------------------
–
---------------------------------
⎞
kΩ
⎝
1.225Δ%
⎠
Δ%
The test results for this configuration are displayed in
Figure 16.
The amount of power delivered by the module is
defined as the voltage at the output terminals multiplied
by the output current. When using remote sense and
trim, 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.
V
I
(+)
ON/OFF
CASE
V
I
(–)
V
O
(+)
SENSE(+)
TRIM
R
adj-down
SENSE(–)
V
O
(–)
8-748b
R
LOAD
Figure 13. Circuit Configuration to Decrease
Output Voltage
ADJUSTMENT RESISTOR VALUE (Ω)
1M
100k
10k
1k
100
0
10
20
30
40
8-879
% CHANGE IN OUTPUT VOLTAGE (Δ%)
Figure 14. Resistor Selection for Decreased
Output Voltage
Lineage Power
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
