CASE 1. Board with 12 BLOCKS

The simplest test case is of 12 power blocks on a board, where each block is 0.25 inches high, except the middle one in the second row from the bottom, which is 0.75 inches high. The power of each block is 1 watt and the board is vertically oriented at natural convection. The data comparisons listed in Table 1 are very satisfactory.

Block Number
Measurement Results
(°C)
BETAsoft Prediction
(°C )
1
57.0
56.3
2
58.0
60.6
3
69.4
70.0
4
66.5
64.7
5
54.2
52.9
6
60.9
60.9
7
64.8
64.0
8
61.1
58.9

 

CASE 2. INFRARED OF TOTAL BOARD

An entire board infrared comparison is made. The powers of components are different. Infrared measurements are made for the board at the real operational condition of natural convection. The actual board has resistors and capacitors located on the back side. A quick first time run of the case was performed with only the major components on the front side modeled. The comparison temperatures of 20 randomly picked IC components across the board are listed in the table below and in general show good accuracy.

Number
IR Scan
BETAsoft
1
82.8
81.6
2
82.9
85.0
3
84.7
84.2
4
84.3
83.7
5
90.4
90.3
6
82.7
84.0
7
81.7
81.3
8
81.1
82.8
9
79.1
83.3
11
88.1
89.0
12
82.9
80.8
13
82.3
79.9
14
86.6
84.4
15
77.7
78.9
16
76.4
77.4
17
75.5
76.4
18
77.8
76.2
19
73.1
75.5
20
74.2
74.8

 

CASE 3. AEROSPACE BOARD TESTS

An example case selected to illustrate the modeling techniques in aerospace thermal design is an engine controller design by AlliedSignal Aerospace. The engine controller is subjected to severe environmental constraints. After all the simulation and any design iterations were completed on the engine controller, an initial prototype was developed and tested. Controlled testing was conducted on the design, and data was collected for the many components with significant power dissipation. The test was conducted in a temperature chamber with a 71C ambient, and thermocouples were used to record the temperature rise of the components. The table below shows the measured results versus the BETAsoft-Board prediction.

Reference Designator
Test Data Junction Temp
BETAsoft-Prediction Junction Temp
cr9
97.20
98.90
cr14
91.70
92.00
cr20
85.23
86.30
g15
85.99
84.70
u12
88.40
87.70
u24
88.37
88.90
u25
86.67
88.40
u31
89.50
87.60
u32
87.90
89.40
u34
89.90
92.70
u44
87.75
88.30
u50
88.11
89.40
u53
86.05
87.30
u54
85.95
86.30
u56
88.05
88.60
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Dynamic Soft Analysis, Inc.
P. O. Box 8119 • Pittsburgh • PA • 15217
Tel: 412.422.3270
email: BETAsoft_info@mentor.com
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