Q48SG12034NRFA Datasheet, PDF (21/26 Pages) Delta Electronics, Inc. – Delphi Series Q48SG Quarter Brick Family Full Digital Control DC/DC Power Modules:

FEATURES DESCRIPTIONS (CON.)
Output Voltage Adjustment (TRIM)
To increase or decrease the output voltage set point,
connect 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. Below Trim equation is
only adapt to the module without droop current sharing
option code; For the module with droop current sharing
option code, please contact Delta’s technical support
team.
Figure 19: 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. 19). The external resistor value required to obtain
a percentage of output voltage change △% is defined
as:
Rtrim

down



511


10.2_{}K
Ex. When Trim-down -10% (12V×0.9=10.8V)
Rtrim

down



511
10

10.2_{}K

40.9K
THERMAL CONSIDERATIONS
Thermal management is an important part of the system
design. To ensure proper, reliable operation, sufficient
cooling of the power module is needed over the entire
temperature range of the module. Convection cooling is
usually the dominant mode of heat transfer.
Hence, the choice of equipment to characterize the
thermal performance of the power module is a wind
tunnel.
Thermal Testing Setup
Delta’s DC/DC power modules are characterized in
heated vertical wind tunnels that simulate the thermal
environments encountered in most electronics
equipment. This type of equipment commonly uses
vertically mounted circuit cards in cabinet racks in which
the power modules are mounted.
The following figure shows the wind tunnel
characterization setup. The power module is mounted
on a test PWB and is vertically positioned within the wind
tunnel. The space between the neighboring PWB and
the top of the power module is constantly kept at
6.35mm (0.25’’).
FANCING PWB
PWB
MODULE
Figure 20: Circuit configuration for trim-up (increase output
voltage)
If the external resistor is connected between the TRIM
and Vo (+) the output voltage set point increases (Fig.
20). The external resistor value required to obtain a
percentage output voltage change △% is defined as:
Rtrim  up  ^{5.11Vo (100   )}  ⁵¹¹ 10.2K
1.225

Ex. When Trim-up +10% (12V×1.1=13.2V)
Rtrim  up  ^{5.1112  (100 10)}  ⁵¹¹ 10.2  489.3K
1.225  10
10
Care should be taken to ensure that the maximum
output power of the module remains at or below the
maximum rated power.
DS_Q48SG12034_06272013
AIR VELOCITY
AND AMBIENT
TEMPERATURE
SURED BELOW
THE MODULE
AIR FLOW
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
Figure 21: Wind tunnel test setup
Thermal Derating
Heat can be removed by increasing airflow over the
module. To enhance system reliability; the power
module should always be operated below the maximum
operating temperature. If the temperature exceeds the
maximum module temperature, reliability of the unit may
be affected.
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