GE Industrial Solutions QRW025 Series User Manual
Page 21
Lineage Power
21
Data Sheet
August 23, 2010
36 Vdc - 75 Vdc Input, 1.2 to 3.3 Vdc Output; 25A
QRW025 Series Power Modules; dc-dc Converters
Feature Descriptions
(Continued)
Output Voltage Set-Point Adjustment (Trim)
Trimming allows the user to increase or decrease the output
voltage set point of a module. This is accomplished by con-
necting 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 (Radj-down), the output voltage set point (Vo,adj)
decreases (see Figure 36). The following equation deter-
mines the required external-resistor value to obtain a per-
centage output voltage change of Δ%.
For Output Voltage: 1.2V - 12V
With an external resistor connected between the TRIM and
SENSE(+) pins (Radj-up), the output voltage set point
(Vo,adj) increases (see Figure 37).
The following equation determines the required external-
resistor value to obtain a percentage output voltage change
of D%
For Output Voltage: 1.5V - 12V
For Output Voltage: 1.2V
The voltage between the Vo(+) and Vo(-) terminals must not
exceed the minimum output overvoltage shut-down value
indicated in the Feature Specifications table. This limit
includes any increase in voltage due to remote-sense com-
pensation and output voltage set-point adjustment (trim). See
Figure 35.
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 volt-
age of the module can be increased, which at the same out-
put 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.
Figure 36. Circuit Configuration to Decrease Output
Voltage.
Figure 37. Circuit Configuration to Increase Output
Voltage.
V
I
(+)
V
I
(–)
ON/OFF
CASE
V
O
(+)
V
O
(–)
SENSE(+)
TRIM
SENSE(–)
R
adj-down
R
LOAD
V
I
(+)
V
I
(–)
ON/OFF
CASE
V
O
(+)
V
O
(–)
SENSE(+)
TRIM
SENSE(–)
R
adj-up
R
LOAD