Data Sheet
April 2008
JAW050A and JAW075A Power Modules; dc-dc Converters:
36 Vdc to 75 Vdc Input, 5 Vdc Output; 50 W to 75 W
Feature Descriptions
(continued)
Remote On/Off
(continued)
I
on/off
+
V
on/off
–
ON/OFF
SENSE(+)
V
O
(+)
LOAD
V
I
(+)
V
I
(–)
V
O
(–)
SENSE(–)
V
I
(+)
SUPPLY
I
I
V
I
(–)
CONTACT
RESISTANCE
V
O
(–)
CONTACT AND
DISTRIBUTION LOSSES
8-651(F).m
SENSE(+)
SENSE(–)
V
O
(+)
I
O
LOAD
Figure 15. Effective Circuit Configuration for
Single-Module Remote-Sense Operation
8-720(F).c
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 16). The following equa-
tion determines the required external-resistor value to
obtain a percentage output voltage change of
Δ%.
1000
R
adj-down
=
⎛
------------
–
11
⎞
kΩ
-
⎝ Δ%
⎠
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 17).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output voltage
change of
Δ%.
Δ%
⎛
(
V
O
,
nom
) (
1 + ---------
)
–
1.225
⎞
-
100
⎜
------------------------------------------------------------------------ 1000
–
11
⎟
kΩ
=
⎜
⎟
1.225Δ%
⎝
⎠
Figure 14. Remote On/Off Implementation
Remote Sense
Remote sense minimizes the effects of distribution
losses by regulating the voltage at the remote-sense
connections. The voltage between the remote-sense
pins and the output terminals must not exceed the out-
put voltage sense range given in the Feature Specifica-
tions table, i.e.:
[V
O
(+) – V
O
(–)] – [SENSE(+) – SENSE(–)]
≤
0.5 V
The voltage between the V
O
(+) and V
O
(–) terminals
must not exceed the minimum output overvoltage pro-
tection voltage as indicated in the Feature Specifica-
tions table. This limit includes any increase in voltage
due to remote-sense compensation and output voltage
set-point adjustment (trim). See Figure 15.
If not using the remote-sense feature to regulate the
output at the point of load, then connect SENSE(+) to
V
O
(+) and SENSE(–) to V
O
(–) at the module.
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.
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.
Lineage Power
R
adj-up
The voltage between the V
O
(+) and V
O
(–) terminals
must not exceed the minimum output overvoltage pro-
tection voltage as indicated in the Feature Specifica-
tions table. This limit includes any increase in voltage
due to remote-sense compensation and output voltage
set-point adjustment (trim). See Figure 15.
9
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
