Data Sheet
JNW350R Power Modules; DC-DC Converters
36 – 75 Vdc Input; 28Vdc Output; 350W Output
July 27, 2009
33
31
Feature Description (continued)
Remote sense
29
Upper Trim Limit
27
25
23
Remote sense minimizes the effects of distribution
losses by regulating the voltage at the remote-sense
connection (see Figure 11). For No Trim or Trim down
application, the voltage between the remote-sense pin
and the output terminal must not exceed the output
voltage sense range given in the Feature
21
19
17
15
Lower Trim Limit
Specifications table i.e.: SENSE(+) – Vo(+) ≤ 2% of
35
40
45
50
55
60
65
70
75
Vo,nom
.
Vin (V)
The voltage between the Vo(+) and Vo(-) terminals
must not exceed the minimum output overvoltage
shut-down value indicated in the Feature
Figure 12. Output voltage trim limits vs. Input
Voltage.
Specifications table. This limit includes any increase
in voltage due to remote-sense compensation and
output voltage set-point adjustment (trim). See Figure
11. Do not connect SENSE(-) to the Vo(-) or Rload(-) as
there is a 0ꢀ connection internal to the module. If not
using the remote-sense feature to regulate the output
at the point of load, then connect SENSE(+) to Vo(+).
Modules without the –T Option
Trim Down – Decrease Output Voltage
Trimming down is accomplished by connecting an
external resistor between the TRIM pin and the
SENSE(-) pin. With an external resistor (Radj-down
between the TRIM and SENSE(-) pins, the output
voltage set point (Vo,adj) decreases (see Figure 13).
The following equation determines the required
external-resistor value to obtain a percentage output
voltage change of Δ%.
)
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. 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.
For output voltages: 28V
100
⎛
⎜
⎞
⎠
Radj − down
=
− 2 kΩ
⎟
Δ%
⎝
Where,
V
o, nom −Vdesired
Δ% =
×100
Vo, nom
V
desired = Desired output voltage set point (V).
Figure 11. Effective Circuit Configuration for
Single-Module Remote-Sense Operation Output
Voltage.
Output Voltage Programming
Trimming allows the user to increase or decrease the
output voltage set point of a module. The trim resistor
should be positioned close to the module. Certain
restrictions apply to the input voltage lower limit when
trimming the output voltage to the maximum. See
Figure 12 for the allowed input to output range when
using trim. If not using the trim down feature, leave
the TRIM pin open.
Figure 13. Circuit Configuration to Decrease
Output Voltage, Standard JNW350R.
Trim Up – Increase Output Voltage
Trimming up is accomplished by connecting external
resistor between the SENSE(+) pin and TRIM
pin.With an external resistor (Radj-up) connected
between the SENSE(+) and TRIM pins, the output
voltage set point (Vo,ad ) increases (see Figure 14).
j
LINEAGE POWER
8
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
