Tyco Electronics Corp.
9
Data Sheet
October 1997
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Feature Descriptions (continued)
Remote On/Off (continued)
8-720 (C).c
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.:
[VO(+) – VO(–)] – [SENSE(+) – SENSE(–)]
≤ 1.2 V
The voltage between the VO(+) and VO(–) terminals
must not exceed 5.9 V. This limit includes any increase
in voltage due to remote-sense compensation and out-
put 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
VO(+) and SENSE(-) to VO(-) at the module.
8-651 (C).h
Figure 15. 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. With an external resistor between the
TRIM and SENSE(–) pins (Radj-down), the output voltage
set point (Vo, adj) decreases (see Figure 16). The follow-
ing equation determines the required external-resistor
value to obtain a percentage output voltage change of
∆%.
The test results for this configuration are displayed in
Figure 17. This figure applies to all output voltages.
With an external resistor connected between the TRIM
and SENSE(+) pins (Radj-up), the output voltage set
point (VO, adj) increases (see Figure 18).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output voltage
change of
∆%.
The test results for this configuration are displayed in
Figure 19.
The voltage between the VO(+) and VO(–) terminals
must not exceed 5.9V. This limit includes any increase
in voltage due to remote-sense compensation and out-
put voltage set-point adjustment (trim). See Figure 15.
If not using the trim feature, leave the TRIM pin open.
8-748 (C).c
Figure 16. Circuit Configuration to Decrease
Output Voltage
SENSE(+)
VO(+)
SENSE(–)
VO(–)
VI(–)
+
–
Ion/off
ON/OFF
VI(+)
LOAD
Von/off
VO(+)
SENSE(+)
SENSE(–)
VO(–)
VI(+)
VI(–)
IO
LOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY
II
CONTACT
RESISTANCE
Radj-down
100
∆%
----------2
–
kΩ
=
Radj-up
VO 100
∆%
+
()
1.225
∆%
--------------------------------------
100
2
∆%
+
()
∆%
----------------------------------
–
kΩ
=
VI (+)
VI (–)
ON/OFF
CASE
VO (+)
VO(–)
SENSE(+)
TRIM
SENSE(–)
Radj-down
RLOAD
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