This document summarizes a student project to automate transient analysis of a voltage converter. The goals were to create a repeatable process to analyze load transients within a reasonable deviation and determine key figures of merit. The student developed a LabVIEW program to automate transient event triggering, data acquisition, and analysis calculations. The program was able to measure slew rate, settling time, overshoot, undershoot, oscillation count, phase margin, and natural frequency across various input voltages and loads with deviations generally within 7% of the mean. The project provided valuable experience with LabVIEW and automated testing that could benefit the student's career in semiconductors.

1. TI Information – Selective DisclosureTI Information – Selective Disclosure 1
Automated Transient Analysis
Isaias Amaya
8/1/2016
DCS-CDS-Validation

2. Agenda
• About me
• Goals and Objectives
• Major Project
• Takeaways
• Acknowledgements
2

3. About me
• Education: Senior, EE Major,
University of Houston
• Hobbies: Music, Rock-climbing
• Career Goals: Be involved in the
semiconductor industry.
• Attempt to start a music electronics company.
3

4. Goals and objectives
In General:
• Find a possible starting point for my career
• See what Texas Instruments has to offer
For the Project:
• Create a reproducible, repeatable, automated routine that would
analyze a load transient within a reasonable deviation percentage**.
• Algorithm was developed around a converter with Dart Mode.
4

5. Reasons behind the project
• Figures of Merit tell us about the quality of the converter.
– Slew rate
– Settling time
– Over/undershoot
– Oscillation Count
– Phase margin
– Natural frequency
• Why not automate everything?
• Closed loop phase margin readings; quick and easy!
5

6. Development Plan
6
Develop
LabVIEW Code
Automate Load
Transient Event,
DAQ, & Analysis
Review Results,
Adjust Parameters
& Thresholds, and
Re-Analyze

7. Phase Margin Math
α δ Q φm
7
Ratio
Between
Overshoots
Ln(α)=δ
Logarithmic
Decrement
Quality
Factor
𝑄 = (
𝜋
δ
)2+
1
4
Phase
Margin
φm=cos−1(
4𝑄4+1−1
2𝑄2 )
[1]Basso, Christophe P. Designing Control Loops for Linear and Switching Power Supplies. Artech House, 2012.
[1] [1]

8. Phase Margin Math
8
α =
𝐵
𝐶

9. Phase Margin Math
9
Y
X
𝑌
𝑋
=α
DC
Level

10. LabVIEW Flowchart
10
Vout
t0
δt
Trigger Over&
Undershoot
Threshold
Cross Finder
Frequency
Find Max &
Min Values
Slew Rate
System
Response
TransientAnalysis
Switch
Node
Natural Frequency
Raw
Data

11. LabVIEW Algorithms
11

12. Automate Load Transient, DAQ, & Analysis
12
-Electric Load
(not pictured):
-Signal Generator
-Voltage Supplies
DartFish
Validation
Board
Tektronix TDS3054B Oscilloscope
NI Chassis
(GPIB
Connections)

13. Accuracy & Repeatability
13
QuickSweep 1:
Rising/Falling
Transient
Initialize
Instruments
QuickSweep 2:
FreqTransient,Vin, &Iload
Setup case
paramenters
QuickSweep 3:
Repeat 30 Times
Acquire, Analyze,
and Store Transient
Data
Terminate
Sequence
i < 30?
j < 24?
k < 2?
Yes
Yes
Yes
No
No
No
Statistical
Analysis

14. Results
4Vin Mean StdDev/Mean
Slew Rate [V/msec] 79.23 5.72%
Settling Time [s] 3.7850E-05 2.15%
Overshoot% 1.074 3.94%
Undershoot% -6.105 -2.61%
Oscillation Count 2 0.00%
Min Value [V] 0.8473 0.14%
Max Value [V] 0.9108 0.04%
Phase Margin [deg] 26.68 7.01%
Natural Frequency
[Hz] 44281 3.34%
14
Measurement Transient VI Bode Plot
Phase Margin 26.68° 35.2°
Natural [VI] &
Crossover[Plot] Frequency
44.28KHz 45.77KHz

15. Results
8Vin Mean StdDev/Mean
Slew Rate [V/msec] 84.97 4.68%
Settling Time [s] 3.7905E-05 1.74%
Overshoot% 1.541 3.58%
Undershoot% -6.778 -3.29%
Oscillation Count 2 0.00%
Min Value [V] 0.8418 0.19%
Max Value [V] 0.9144 0.06%
Phase Margin [deg] 32.57 6.69%
Natural Frequency
[Hz] 44991 4.29%
15
Measurement Transient VI Bode Plot
Phase Margin 32.57° 32.67°
Natural [VI] & Crossover[Plot]
Frequency
44.99KHz 46.28KHz

16. Results
12Vin Mean StdDev/Mean
Slew Rate [V/msec] 90.96 6.69%
Settling Time [s] 3.1990E-05 2.32%
Overshoot% 1.459 4.87%
Undershoot% -6.366 -3.19%
Oscillation Count 2 0.00%
Min Value [V] 0.8451 0.19%
Max Value [V] 0.9136 0.06%
Phase Margin [deg] 33.86 8.11%
Natural Frequency
[Hz] 54061 4.71%
16
Measurement Transient VI Bode Plot
Phase Margin 33.86° 33.47°
Natural [VI] &
Crossover[Plot] Frequency
54.06KHz 49.15KHz

17. Results
16Vin Mean StdDev/Mean
Slew Rate [V/msec] 97.54 8.29%
Settling Time [s] 2.7613E-05 2.18%
Overshoot% 1.460 7.22%
Undershoot% -5.932 -2.82%
Oscillation Count 2 0.00%
Min Value [V] 0.8484 0.14%
Max Value [V] 0.9134 0.10%
Phase Margin [deg] 37.02 11.32%
Natural Frequency
[Hz] 63160 5.74%
17
Measurement Transient VI Bode Plot
Phase Margin 37.02° 34.54°
Natural [VI] &
Crossover[Plot] Frequency
63.16KHz 51.62KHz

18. Results Summary
• The project was successful.
• Accurate Phase Margin measurement*, high margin of error.
• Repeatable measurements of all the other figures of merit to ±7% from
the mean per std.dev.
• 48 Cases, 1440 iterations in 2.4 hours
– Average Time/Automated Iteration: 6 seconds
– Average Time/Manual Iteration: 20 minutes (assuming the network analyzer
in the G1-F2 Lab is free and working…)
• Slew Rate High Margin of Error 18

19. 19
Slew Rate Glitch (Same Conditions Applied in all 3 cases)

20. Limitations/Challenges of the Code
• Phase Margin Measurement
• Data must be settled at the tail end and beginning
• TestStand sequence is scope-dependent
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21. Next Steps
• Obtain statistical information on every possible Freq/Vin/Iload combination.
• Implement Underdamped, 1 oscillation phase margin calculation
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22. Takeaways
• The learning experience is something that has helped me solidify my
knowledge in LabVIEW
• Texas Instruments has a great environment in which I feel I could thrive
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• The leftovers put out on the G1-F2 lunch tables were nice, too.

23. Acknowledgements
• Special thanks to:
– Matt Roberts
– Mac McIlvaine
– Illya Kovarik
– Dan Katz
– McDavis Fasugba
– Mike Munroe
– Everyone in the G2F1 Design Lab that helped in one way or another.
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