8
GLOBAL ENERGY EFFICIENCY SPECIALIST
Remote On/Off
Figure 15: Various circuits for driving the On/Off pin
Logic
Enable
On/Off Pin Level
Status
Negative
logic
Low level
On
High level or left
open
Off
Remote Sense
Output Voltage Trim
Trim Up
The relationship between R
adj-up
and V
out
:
V
in
(+)
On/Off
V
in
(-)
V
out
(+)
Sense(+)
Trim
Sense(-)
V
out
(-)
R
adj-up
Load
Figure 17: Configuration diagram for Trim up
The output voltage can be increased by installing
an external resistor between the Trim pin and the
Sense(+) pin.
1.
If the Trim pin is not used, it should be left open.
2.
Ensure that the actual output power does not exceed
the maximum output power when raising the voltage.
The output voltage can be adjusted according to
the trim range specification by using the Trim pin.
Trim Down
The output voltage can be decreased by installing
an external resistor between the Trim pin and the
Sense(-) pin.
Figure 18: Configuration diagram for Trim down
The relationship between R
adj-down
and V
out
:
V
in
(+)
On/Off
V
in
(-)
V
out
(+)
Sense(+)
Trim
Sense(-)
V
out
(-)
R
adj-down
Load
Simple control
On/Off
V
in
(-)
On/Off
V
in
(-)
On/Off
V
in
(-)
On/Off
V
in
(-)
Transistor
control
Isolation control
Direct logic drive
VCC
TTL/
COMS
GAQ37S12B-4
DC-DC Converter Technical Manual V1.0
Figure 16: Configuration diagram for remote sense
This function is used to compensate for voltage
drops on R
w
. The Sense(+), Sense(-), V
out
(+), and
V
out
(-) terminals should meet the following
requirements:
V
in
(+)
On/Off
V
in
(-)
V
out
(+)
Sense(+)
Trim
Sense(-)
V
out
(-)
R
w
Load
R
w
R
w
indicates the line impedance between the output terminal
and the load.
If the remote sense function is disabled, the
Sense(+) terminal directly connects to the V
out
(+)
terminal and the Sense(-) terminal directly
connects to the V
out
(-) terminal.
[V
out
(+)
– V
out
(
–)] – [Sense(+) – Sense(–)] ≤ 10% x V
nom
(V
nom
is the rated output voltage.)
)
(
22
.
10
511
225
.
1
)
100
(
11
.
5
k
V
R
nom
up
adj
100
nom
nom
out
V
V
V
100
nom
out
nom
V
V
V
)
(
22
.
10
511
k
R
down
adj
