Delta Electronics Q48DC manual Thermal Considerations, Thermal Testing Setup, Thermal Derating

Page 11

THERMAL CONSIDERATIONS

THERMAL CURVES

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

Figure 20: Temperature measurement location

 

 

 

 

circuit cards in cabinet racks in which the power modules

 

 

 

 

are mounted.

 

 

* The allowed maximum hot spot temperature is defined at 124

The following figure shows the wind tunnel characterization

3.0

 

Q48DC12003(Standard) Output Current vs. Ambient Temperature and Air Velocity

 

 

 

 

 

 

@Vin = 48V (Transverse Orientation)

 

 

 

 

 

 

 

 

 

Output Current(A)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

setup. The power module is mounted on a test PWB and is

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

vertically positioned within the wind tunnel.

The space

2.5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

between the neighboring PWB and the top of the power

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

module is constantly kept at 6.35mm (0.25’’).

2.0

 

 

 

 

 

 

 

Natural

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Convection

 

 

 

 

 

 

 

Thermal Derating

 

 

 

 

 

 

 

 

 

 

 

100LFM

 

 

 

 

 

 

 

 

1.5

 

 

 

 

 

 

 

 

 

200LFM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Heat can be removed by

increasing airflow over the

1.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

module.To enhance system reliability, the power module

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

should always be operated below the maximum operating

0.5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

temperature. If the temperature exceeds the maximum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

module temperature, reliability of the unit may be affected.

0.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

25

30

35

40

45

50

55

60

65

70

75

80

85

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ambient Temperature ()

FACING PWB

PWB

Figure 21: Output current vs. ambient temperature and air velocity

 

 

 

 

MODULE

@Vin = 48V(Transverse Orientation)

 

 

 

 

 

 

 

 

 

AIR VELOCITY

 

AND AMBIENT

 

TEMPERATURE

 

MEASURED BELOW

50.8 (2.0”)

THE MODULE

 

AIR FLOW

12.7 (0.5”)

Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)

Figure 19: Wind Tunnel Test Setup

DS_Q48DC12003_03112008

11

Image 11
Contents Options Parameter Technical SpecificationsElectrical Characteristics Curves Electrical Characteristics Curves 1µF ceramic capacitor. Top trace Vout 100mV/div Electrical Characteristics Curves Scope Resistiv Input Source Impedance Design ConsiderationsOver-Voltage Protection Features DescriptionsOver-Temperature Protection Over-Current ProtectionOutput Voltage Adjustment Trim Features Descriptions CONThermal Derating Thermal Testing SetupThermal Considerations Pin No Name Function Mechanical DrawingModel List Part Numbering System