Q48DB12003NRFA Datasheet, PDF (10/13 Pages) Delta Electronics, Inc. – Delphi Series Q48DB, 65W Quarter Brick Dual Output DC/DC Power Modules: 48V in, ±12V, 2.7A Output

FEATURES DESCRIPTIONS (CON.)
Output Voltage Adjustment (TRIM)
To increase or decrease the output voltage set point,
the modules may be connected with an external
resistor between the TRIM pin and either the Vo(+) or
Vo(-). The TRIM pin should be left open if this feature
is not used.
Vo(+)
Trim
Rtn
Vo(-)
R_trim-down
R_Load
Figure 17: Circuit configuration for trim-down (decrease
output voltage)
If the external resistor is connected between the TRIM
and Vo(-) pins, the output voltage set point decreases
(Fig.17). The external resistor value required to obtain
a percentage of output voltage change △% is defined
as:
Rtrim
−
down
=
⎡ 511
⎢⎣ _∆
−
10
.2
⎤
⎥⎦
(K
Ω
)
Ex. When Trim-down -10%(12V×0.9=10.8V)
Rtrim
−
down
=
⎡ 511
⎢⎣ ₁₀
− 10.2_{⎥⎦⎤}(KΩ ) =
40 .9(KΩ )
If the external resistor is connected between the TRIM and
Rtn the output voltage set point increases (Fig.18). The
external resistor value required to obtain a percentage
output voltage change △% is defined as:
Rtrim − up = ^{5.11×Vo × (100 + ∆)} − ⁵¹¹ −10.2(KΩ)
1.225 × ∆
∆
Ex. When Trim-up +10%(12 V×1.1=13.2V)
Rtrim − up = ^{5.11×12 × (100 +10)} − ⁵¹¹ −10.2 = 489(KΩ)
1.225 ×10
10
When using trim, the output voltage of the module is usually
increased, which increases the power output of the module
with the same output current.
Care should be taken to ensure that the maximum output
power of the module remains at or below the maximum rated
power.
Vo(+)
Trim
Rtn
Vo(-)
R_trim-up
RLoad
Figure 18: Circuit configuration for trim-up (increase output
voltage)
DS_Q48DB12003_04182006
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