Thermal considerations – GE Industrial Solutions Austin Lynx II SIP User Manual

Page 15

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Data Sheet
October 2, 2009

Austin Lynx

TM

II SIP Non-isolated Power Modules:

2.4 – 5.5Vdc input; 0.75Vdc to 3.63Vdc Output; 10A output current


LINEAGE

POWER

15

Thermal Considerations

Power modules operate in a variety of thermal
environments; however, sufficient cooling should always
be provided to help ensure reliable operation.

Considerations include ambient temperature, airflow,
module power dissipation, and the need for increased
reliability. A reduction in the operating temperature of
the module will result in an increase in reliability. The
thermal data presented here is based on physical
measurements taken in a wind tunnel. The test set-up
is shown in Figure 35. Note that the airflow is parallel to
the long axis of the module as shown in figure 34. The
derating data applies to airflow in either direction of the
module’s long axis.

Airflow

Tref

Top View

Figure 34. Tref Temperature measurement location.

The thermal reference point, T

ref

used in the

specifications is shown in Figure 34. For reliable
operation this temperature should not exceed 115

o

C.

The output power of the module should not exceed the
rated power of the module (Vo,set x Io,max).
Please refer to the Application Note “Thermal
Characterization Process For Open-Frame Board-
Mounted Power Modules” for a detailed discussion of
thermal aspects including maximum device
temperatures.

Heat Transfer via Convection

Increased airflow over the module enhances the heat
transfer via convection. Thermal derating curves
showing the maximum output current that can be
delivered at different local ambient temperature (T

A

) for

airflow conditions ranging from natural convection and
up to 2m/s (400 ft./min) are shown in the Characteristics
Curves section.





Figure 35. Thermal Test Set-up.

Air

flow

x

Power Module

Wind Tunnel

PWBs

8.3_

(0.325)

76.2_

(3.0)

Probe Location
for measuring
airflow and
ambient
temperature

25.4_

(1.0)

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