DS_IPM12S0A008_03202007

11

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 height of this fan duct is constantly kept

at 25.4mm (1

’’).

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.

MODULE

AIR FLOW

12.7

(0.5”)

50.8 (2.0”)

FACING PWB

PWB

AIR VELOCITY

AND AMBIENT

TEMPERATURE

MEASURED BELOW

THE MODULE

25.4 (1

.0”)

Figure 32: Wind tunnel test setup figure

THERMAL CURVES

Figure 33: Temperature measurement location

* The allowed maximum hot spot temperature is defined at 113

IPM12S(Standard) Output Current vs. Ambient Temperature and Air Velocity

@ Vin = 12V, Vo = 5V (Either Orientation)

0

1

2

3

4

5

6

7

8

9

35

40

45

50

55

60

65

70

75

80

85

Ambient Temperature (℃)

Output Current(A)

Natural

Convection

100LFM

200LFM

300LFM

400LFM

500LFM

600LFM

Figure 34: Output current vs. ambient temperature and air velocity

@ Vin=12V, Vo=5V

IPM12S(Standard) Output Current vs. Ambient Temperature and Air Velocity

@ Vin = 12V, Vo = 3.3V (Either Orientation)

0

1

2

3

4

5

6

7

8

9

35

40

45

50

55

60

65

70

75

80

85

Ambient Temperature (℃)

Output Current(A)

Natural

Convection

100LFM

200LFM

300LFM

400LFM

500LFM

Figure 35: Output current vs. ambient temperature and air velocity

@ Vin=12V, Vo=3.3V