background image

10

SAT draws the Bode plot of the voltage loop gain on the right half of the page as

shown in Figure 5. The phase margin, which is a measure of stability, and the gain
crossover frequency, which is a measure of fast transient response, are also
calculated and presented below the Bode plot.

You can enter your notes under the "Notepad Area for JFW050A Module" section

in the left lower corner of the page. You can also edit the circuit parameters and
simulate various what-if scenarios and record the results on the same page. Figure 6
below compares two scenarios where the value of C

b2

is changed from 1000

µ

F to

6800

µ

F.

 

To investigate a different configuration, click on the

Configuration Menu

tab at

the bottom of the Excel worksheet which will take you back to the configuration-
selection page. If you click on the circuit diagram for Configuration 2, the page for
that configuration will appear in the window and the Configuration 4 page will
disappear (Figure 7). You can now repeat the analysis in a manner similar to the
previous case. There is no need to re-load the module data file for JFW050A to
perform an analysis for another configuration.

R

load

=

0.5

ohm

R

s1

=

1

R

s2

=

5

mohm

L

s1

=

4

L

s2

=

100

nH

R

a1

=

100

R

a2

=

100

R

a3

=

10

R

b1

=

10

R

b2

=

10

mohm

L

a1

=

1

L

a2

=

1

L

a3

=

1

L

b1

=

10

L

b2

=

10

nH

C

a1

=

10

C

a2

=

10

C

a3

=

1000

C

b1

=

1000

C

b2

=

1000

µ

F

Hz

degrees

Stability Analysis Tool

Notepad Area for JFW050A Module

Please enter the circuit parameters below

Gain crossover frequency:

Phase Margin:

Phase of the Loop Gain

-180

-120

-60

0

60

120

180

10

100

1000

10000

100000

Frequency (Hz)

P

h

ase

(d

eg)

Magnitude of the Loop Gain

-40

-20

0

20

40

60

10

100

1000

10000

100000

Frequency (Hz)

Ga

in

(d

B)

Click to Calculate Stability

C

a 1

L

S1

R

S1

R

a 1

R

L

DC /DC

C O NVERTER

L

a1

C

a2

R

a2

L

a2

SENSE

L

S2

R

S2

C

b1

R

b1

L

b1

C

a3

R

a3

L

a3

C

b2

R

b2

L

b2

Fig. 4. Page for entering and editing circuit parameters, shown for the case of
configuration 4.

Summary of Contents for Stability Analysis Tool

Page 1: ...TYCO ELECTRONICS POWER SYSTEMS 3000 SKYLINE DRIVE MESQUITE TX 75149 StabilityAnalysisTool User sGuide For use with BoardMounted DC DCconverters V1 3...

Page 2: ...e that it is error free nor does Tyco Electronics make any representations warranty or guarantee that the Information is accurate correct reliable or up to date Tyco Electronics expressly disclaims al...

Page 3: ...nts or employees will operate to create any warranty or guarantee or vary any provision or information herein and you may not rely on any such information or advice Tyco Electronics reserves the right...

Page 4: ...voltage sense location are unknown Due to this in the past if the customer wanted to determine stability margins the loop gain would have to be measured using a breadboard of the power supply and the...

Page 5: ...en an Excel Worksheet and follow the directions on the screen Make sure that the Analysis Toolpak Add ins are enabled in Excel Go to Tools menu in Excel and click on Add Ins Check tick on Analysis Too...

Page 6: ...6 Using SAT When you start SAT you will see the window shown in Figure 1 2 Fig 1 SAT Introduction and Module Selection page...

Page 7: ...ata files for the particular modules you wish to analyze they will need to be downloaded before you can use the tool Choose the module that you want to use in your application by selecting the corresp...

Page 8: ...eries combination of equivalent series resistance ESR and equivalent series inductance ESL If all the capacitors are the same type e g aluminum electrolytic and capacitance value e g 6800 F then this...

Page 9: ...r two types of capacitors you can still use the model by setting the values corresponding to the other capacitor to zero The second capacitor bank is typically placed as close as possible across the l...

Page 10: ...figuration 2 the page for that configuration will appear in the window and the Configuration 4 page will disappear Figure 7 You can now repeat the analysis in a manner similar to the previous case The...

Page 11: ...Ra3 La3 Cb2 Rb2 Lb2 Fig 5 Voltage loop response Bode plot with phase margin and gain crossover frequency calculated and displayed Rload 0 5 ohm Rs1 1 Rs2 5 mohm Ls1 4 Ls2 100 nH Ra1 100 Ra2 100 Ra3 10...

Page 12: ...oad 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 o...

Page 13: ...system as well This method assumes that the layout is symmetrical in the sense that all parasitic impedances between the modules and the load are substantially equal and the sense locations of all mo...

Page 14: ...ge is at the nominal value e g 48V for xWxxx 24V for xCxx modules etc The loop response and phase margin will be different if the input voltage is not at the nominal value However for stability assess...

Page 15: ...the Analysis Toolpack and Analysis Toolpack VBA in your Excel environment as desribed in page 5 of this document under Installation and Usage If you cannot see Analysis Toolpack and Analysis Toolpack...

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