Data Sheet
QPW050/060 Series Power Modules; DC-DC converters
36-75Vdc Input; 1.2Vdc to 3.3Vdc Output
March 27, 2008
The amount of power delivered by the module is
defined as the voltage at the output terminals
Feature Description (continued)
Output Voltage Set-Point Adjustment (Trim)
resistor value to obtain a percentage output voltage
change of Δ%.
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: 1.5V – 3.3V
510
⎛
⎜
⎞
⎠
Radj − down
=
−10.2 KΩ
⎟
Δ%
⎝
For output voltage: 1.2V
1299.1
⎛
⎜
⎞
⎠
Radj − down
=
− 33.49 KΩ
⎟
Δ%
⎝
Where,
V
o, nom −Vdesired
Δ% =
×100
Vo, nom
Vdesired = Desired output voltage set point (V).
With an external resistor connected between the
TRIM and SENSE(+) pins (Radj-up), the output
voltage set point (Vo,adj) increases (see Figure 37).
Figure 36. Circuit Configuration to Decrease
Output Voltage .
The following equation determines the required
external-resistor value to obtain a percentage output
voltage change of Δ%.
For output voltages: 1.5V – 3.3V
5.1*Vo, nom
*
100 + Δ%
)
510
⎛
⎜
⎞
⎠
Radj − up
=
−
−10.2 KΩ
⎟
1.225*Δ%
Δ%
⎝
For output voltage: 1.2V
9.769*Vo, nom
*
100+Δ%
)
1299.1
⎛
⎜
⎞
⎠
Figure 37. Circuit Configuration to Increase
Output Voltage.
R
adj − up
=
−
−33.49 KΩ
⎟
0.6*Δ%
Δ%
⎝
Examples:
Where,
To trim down the output of a nominal 3.3V
module (QPW050A0F) to 3.1V
V
desired −Vo, nom
Δ% =
×100
Vo, nom
3.3V − 3.1V
Vdesired = Desired output voltage set point (V).
Δ% =
×100
3.3V
∆% = 6.06
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 compensation and
output voltage set-point adjustment (trim). See Figure
35.
510
⎛
⎜
⎞
⎠
Radj − down
=
−10.2 KΩ
⎟
6.06
⎝
Radj-down = 73.96 kΩ
To trim up the output of a nominal 3.3V module
(QPW050A0F) to 3.6V
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.
3.6V − 3.3V
Δ% =
×100
3.3V
LINEAGE POWER
14
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