Delta Electronics ND Series manual Thermal Consideration, Thermal Testing Setup, Thermal Derating

THERMAL CONSIDERATION THERMAL CUREVES `

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

Figure 32: Temperature measurement location* The allowed

environments encountered in most electronics

maximum hot spot temperature is defined at 124℃

equipment. This type of equipment commonly uses

vertically mounted circuit cards in cabinet racks in which

Output Current (A)

Output Current vs. Ambient Temperature and Air Velocity

ND12S0A0V50(standard)

the power modules are mounted.

55

@Vin=12V Vout=0.9V (Through PCB Orientation)

The following figure

shows

the wind

tunnel

50

45

characterization setup. The power module is mounted

Natural

40

Convection

on a test PWB and is vertically positioned within the

35

wind tunnel. The space between the neighboring PWB

100LFM

30

and the top of the power module is constantly kept at

25

200LFM

6.35mm (0.25’’).

20

Thermal Derating

15

10

Heat can be removed by increasing airflow over the

5

0

module. To enhance

system

reliability, the

power

Ambient Temperature (℃)

25

30

35

40

45

50

55

60

65

70

75

80

85

module should always be operated below the maximum

Figure

33: Output

current

vs. ambient

temperature

and

air

operating temperature. If the temperature exceeds the

velocity @Vin=12V, Vout=0.9V(Through PCB Orientation)

maximum module temperature, reliability of the unit may

be affected.

ND12S0A0V50(standard)

Output Current vs. Ambient Temperature and Air Velocity

Output Current (A)

@Vin=12V Vout=2.5V (Through PCB Orientation)

	PWB	55
FACING PWB		50
		45
	MODULE	40		Natural
				Convection
		35
		30				100LFM
								200LFM
AIR VELOCITY		25								300LFM
AND AMBIENT
		20
TEMPERATURE
MEASURED BELOW	50.8 (2.0”)	15
THE MODULE
AIR FLOW		10
		5
		0
	11 (0.43”)	25	30	35	40	45	50	55	60	65	70	75	80	85
												Ambient Temperature (℃)
	22 (0.87”)	Figure 34: Output current vs. ambient temperature and air
Note: Wind tunnel test setup figure dimensions are in
		velocity@ Vin=12V, Vout=2.5V(Through PCB Orientation)
millimeters and (Inches)
Figure 31: Wind tunnel test setup
DS_ND12S10A_07172008

10