GE Industrial Solutions QRW010-025-035-040 Series User Manual
Page 31
Lineage Power
31
Data Sheet
August 24, 2010
36 Vdc - 75 Vdc Input, 1.0 to 12 Vdc Output; 10 A to 40 A
QRW010/025/035/040 Series Power Modules; dc-dc Converters
Thermal Considerations
The power modules operate in a variety of thermal environ-
ments; however, sufficient cooling should be provided to help
ensure reliable operation of the unit. Heat-dissipating compo-
nents are mounted on the top side of the module. Heat is
removed by conduction, convection and radiation to the sur-
rounding environment. Proper cooling can be verified by
measuring the temperature of selected components on the
topside of the power module (See 56). Peak temperature
(Tref) can occur at any of these positions indicated in Figure
50.
Note:Top view, pin locations are for reference only.
Figure 56. Temperature Measurement Location.
The temperature at any one of these locations should not
exceed per 1 to ensure reliable operation of the power mod-
ule. The output power of the module should not exceed the
rated power for the module as listed in the Ordering Informa-
tion table.
Although the maximum Tref temperature of the power mod-
ules is per 1, you can limit these temperatures to a lower
value for extremely high reliability.
Table 1.
Device Temperature
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat trans-
fer via convection. Figures 57 through 64 shows the maxi-
mum current that can be delivered by the corresponding
module without exceeding the maximum case temperature
versus local ambient temperature (TA) for natural convection
through 2 m/s (400 ft./min.).
Note that the natural convection condition was measured at
0.05 m/s to 0.1 m/s (10ft./min. to 20 ft./min.); however, sys-
tems in which these power modules may be used typically
generate natural convection airflow rates of 0.3 m/s (60 ft./
min.) due to other heat dissipating components in the system.
The use of output power derating curve is shown in the fol-
lowing example.
What is the minimum airflow necessary for a QRW035A0F
operating at VI = 48 V, an output current of 23A, and a maxi-
mum ambient temperature of 70 °C.
Solution
Given: VI = 48V
Io = 23A
TA = 70 °C
Determine airflow (v) (Use Figure 62):
v = 1m/sec. (200ft./min.)
Figure 57. Output Power Derating for QRW040A0S1R0
(Vo = 1.0V) in Transverse Orientation with No
Baseplate; Airflow direction from VIN (+) to
VIN (–); VIN = 48V.
Figure 58. Output Power Derating for QRW040A0P (Vo =
1.2V) in Transverse Orientation with No
Baseplate; Airflow direction from VIN (+) to
VIN (–); VIN = 48V.
Output Voltage
Device
Temperature (°C)
1.0V
Tref1
116
1.2V
Tref1
119
1.5V
Tref1
118
1.8V
Tref1
117
2.5V
Tref1
118
3.3V
Tref1
Tref2
Tref3
114
112
130
5V
Tref1
113
12V
Tref1
118
OUTPUT
INPUT
Airflow
Thermocouple
Location T
ref
3
Thermocouple
Location T
ref
2
Thermocouple
Location T
ref
1
LOCAL AMBIENT TEMPERATURE, T (°C)
A
OUT
P
UT
C
URR
ENT
, I
(A
)
O
40
35
30
25
20
15
10
5
0
20
30
40 50
60
70
80 90
LOCAL AMBIENT TEMPERATURE, T (°C)
A
OUT
P
UT
C
U
RRE
NT
, I
(A
)
O