Tyco TX 75149 - Manual (Page 12)

12
To analyze a different module, you should select the
Module Selection
tab at
the bottom of the Excel Worksheet to go back to the first page and load the data
file for the new module. Note that the new data file will overwrite the old one
belonging to the JFW050A. If you want to keep your analysis results for the
JFW050A module, you should save SAT_v1.3.xls under a different name, e.g.
JFW050A.xls.
Paralleled Modules
Paralleled modules can also be analyzed using SAT. Typically, in systems
with paralleled modules, active current sharing is used to distribute the stresses
evenly between modules. As described in [1], such a system can be analyzed
separately for common-mode stability (which is solely dependent on the number of
modules, the characteristics of the modules and the load), and differential-mode
stability (which only depends on the current-sharing loop and is independent of the
number of modules paralleled or the load). Since differential-mode stability is
independent of the load, the manufacturer of the module is able to ensure that the
current-sharing loop is stable. However, common-mode stability depends both on
the number of modules paralleled and the load, both of which are controlled by the
R
load
= 0.054 ohm
R
s1
= 1 mohm
L
s1
= 28 nH
R
a1
= 9 mohm
L
a1
= 0 nH
C
a1
= 10000
µ F
229.1 Hz
52.93 degrees Phase Margin:
Stability Analysis Tool
Notepad Area for JFW050A Module
Please enter the circuit parameters below
Gain crossover frequency:
Phase of the Loop Gain
-180
-120
-60
0
60
120
180
100 1000 10000 100000
Frequency (Hz)
P
h
ase
(d
eg)
Magnitude of the Loop Gain
-80
-60
-40
-20
0
20
40
100 1000 10000 100000
Frequency (Hz)
Ga
in
(d
B
)
Clic k to Ca lcula te Sta bility
C
a1
L
S1
R
S1
R
a1
R
L
DC/DC
CONVERTER
L
a1
SENSE
Fig. 7. Stability analysis of the JFW050A for Configuration 2.