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The 5-Minute Method for Stabilizing Any Control Loop

By Steve Sandler | January 28, 2020 One method of designing stable control loops is to create an accurate broadband simulation model and to use pole zero compensation to optimize phase margin, gain margin and stability margin…” Click here to read entire article #j2102b #design #ESR #j2100aj2101a #articles #2portshunt #applicationnotes #bode100 #nism #dcdcconverter #noninvasivemeasurement #stability #converter #switchmodepowersupply #spacepower #regulator #bodeplots #controllo

Siglent App Note: Measuring Power Supply Control Loop Response with Bode Plot II

In this application note, we will show you the basic principles for making this stability measurement and how to use these instruments to make the measurement.” Read the entire app note here. #phasemargin #gainmargin #oscilloscopes #j2100aj2101a #powerintegrity #siglent #injection #frequencyresponseanalyzers #feedbackamplifier #powersupply #VNA #picotest #stability #bodeplots #controlloop

Earn IEEE CEU/PDHs and learn the latest design techniques at EDI CON University

All conference pass holders are eligible to attend, but pre-registration happens during the registration process. After attending an EDI CON University course, attendees can earn IEEE Continuing Education Unit/Personal Development Hour (CEU/PDH) certificates and enjoy a complimentary lunch on the expo floor. This year’s EDI CON University sessions are sponsored by Teledyne LeCroy, Mini-Circuits and Keysight Technologies. CLICK HERE to register today. Write a short essay to su

August Book Sale: Get Your Copy of Power Integrity for Only $65

PROVEN TECHNIQUES FOR GENERATING HIGH-FIDELITY MEASUREMENTS Power Integrity: Measuring, Optimizing, and Troubleshooting Power Related Parameters in Electronics Systemsprovides field-tested techniques for producing high-fidelity measurements using the appropriate equipment. The book thoroughly discusses measurement guidelines, test instrument selection and use, connecting the equipment to the device being tested, and interpreting the acquired data. The latest electronics techn

EDI CON USA 2018 Announces EDI CON University

All conference pass holders are eligible to attend, but pre-registration happens during the registration process. After attending an EDI CON University course, attendees can earn IEEE Continuing Education Unit/Personal Development Hour (CEU/PDH) certificates and enjoy a complimentary lunch on the expo floor. This year’s EDI CON University sessions are sponsored by Teledyne LeCroy, Mini-Circuits and Keysight Technologies. CLICK HERE to read the full article and see this year’s

Accurately measure ceramic capacitors by extending VNA range

Ceramic capacitors play an oversized role in circuit performance as a major contributor to voltage regulator control loop stability and power delivery network (PDN) impedance. When designing with these circuit staples, you need good impedance data over a wide frequency range. Proper measurement technique is the key to making accurate measurements. Here’s how to use two simple techniques that result in accurate, wideband, frequency measurements by extending the range of a vect

Top Three EMI and Power Integrity Problems with On-Board DC-DC Converters and LDO Regulators

Kenneth Wyatt Wyatt Technical Services, LLC ken@emc-seminars.comSteve Sandler Picotest Modern devices are continuing a long-term trend of squeezing more electronics into smaller packages, while also increasing system performance, data rates and operating efficiency. Higher efficiencies are often achieved by implementing faster silicon MOSFETs or even faster eGaN FETs while size is reduced by increasing switching frequencies and replacing aluminum and ta

Killing the Bode Plot

Many new linear devices, including voltage references, voltage regulators and opamps have internal feedback loops, prohibiting traditional bode plots. Yet, the assessment of stability is critical, since it directly impacts system performance, including clock jitter and system noise. This session takes a look at a non-invasive stability assessment. The theory behind the measurements, how accurate it is and measurement demonstrations for a variety of devices and setups. View th

Impedance measurements stabilize op-amp buffers

Figure 1. Op amps are often used as unity gain signal buffers, which are not as simple to use as it may appear. The unity-gain op amp (operational amplifier) buffer circuit is routinely used to transform high-impedance inputs into low-impedance outputs. ADC (analog-to-digital converter) voltage references are also frequently buffered to reduce the voltage reference noise resulting from the ADC sampling current. When implemented well, using an appropriate op amp, the results w

Impedance measurements make a difference at DesignCon

What do clock jitter, EMI, control loop stability, SPICE modeling, rogue waves and the ripeness of fruit have in common?  Do you need to develop lower cost, higher performance products, in less time and in a smaller physical space?  Or do you just need to learn the fastest method to troubleshoot issues in distributed systems? At DesignCon 2015 on Tuesday, January 27th from 9AM-12PM we’ll show how impedance plays a role in all of these questions.  This tutorial focuses on how

Paultre on Power – Steve Sandler of Picotest on power test and noise (Podcast)

October 31, 2014 In this podcast Steve Sandler of Picotest talks to Alix Paultre of Power Systems Design on the issues of power test, especially in the area of reducing noise. Not only is noise in a system a potential interference hazard, it is also a sign that the system is not operating optimally. Speed, bandwith, and probe considerations are among the many factors involved in performing proper test. More and more application spaces need clean power and more efficient syste

Three Stability Assessment Methods Every Engineer Should Know About

Many engineers are familiar with the Bode plot as an effective stability assessment method. However, some authors suggest and even teach that the Bode plot is the only method needed. This article shows why this thinking is short-sighted. A single, low cost instrument that can produce Bode plots, as well as two other stability assessment methods is discussed providing a more comprehensive stability assessment set of guidelines. A single word illustrates why Bode plots cannot b

Software Enables Accurate Stability Test, Improves Non-Invasive Phase Margin Measurement Accuracy

The mathematics behind the non-invasive measurement was incorporated into the OMICRON Lab Bode 100 VNA software, sold by, starting in late 2011. The solution was included as a single cursor based measurement utilizing a piecewise linear approximated solution.  The approximate solution is most accurate below 40 degrees, while the method is capable of accurately determining phase margins up to nearly 70 degrees. Thanks to the completion of a license agreement with

Five Things Every Engineer Should Know About Bode Plots

In 1938 Hendrik Wade Bode, who worked at Bell Labs, published his asymptotic assessment of phase margin and gain margin, bearing his name [2]. The Bode plot is recognized for its simplicity and the simple asymptotic approach makes the method useful for both design and assessment of power system control loops.  There have been many other methods introduced since, including Nathaniel Nichol’s stability charts in 1947 [4] and root locus introduced by Walter Evans in 1948 [5].  I

Non-Invasively Assess Your Multiple-Loop LDO’s Stability

Some low-dropout regulators (LDOs) use multiple feedback loops to improve output voltage transient response. In many of these cases, some or all of the loops are inside the IC. Designers can assess the stability of these regulators by using the non-invasive stability measurement capability of the OMICRON Lab Bode 100 vector network analyzer (VNA). The simplified schematic in Figure 1 shows traditional error amplifier feedback along with a second loop that connects some functi

Troubleshooting Distributed Power Systems: Measuring Ripple (Part 7 of the ongoing series)

And by taking measurements across all three test domains, designers can trace power supply ripple-related problems back to root causes such as switching frequency, load dynamics, and PCB crosstalk as explained here. Various test setups, which include instruments from Picotest and other vendors, and measurement techniques are described in this video and results of example ripple measurements using different point of load regulators (POLs) are discussed. Along the way, Sandler

Troubleshooting Distributed Power Systems: The Switch (Part 6 of the ongoing series.)

With those measurement requirements as background, Sandler examines how switching frequency and duty cycle affect power supply stability as well as EMI. Measurements taken at the switch-node reveal information about power supply stability, noise, and EMI and how these characteristics are affected by switching frequency and duty cycle. Click here to watch the video. #oscilloscopes #noise #ripplemeasurements #picotest #videos #emimeasurement #stability #clockjitter #timedomainm

How To Verify Control Loop Design

The non-invasive stability assessment is a method that uses an output impedance measurement to accurately determine stability without access to the control loop. The non-invasive stability assessment, whether performed as a physical test or with a circuit simulation, is a fast, simple, and inexpensive means to verify or optimize any control loop design.  This measurement is useful in almost all systems, though especially in high-speed, instrumentation, and RF systems.  Improv

Troubleshooting Distributed Power Systems: Using Current Injectors (Part 5 of the ongoing video seri

Although not quite as accurate as the two-port VNA impedance measurement, the current injection technique has advantages including wide range (approx. 1 milli-ohm to thousands of ohms), the ability to measure in-system, and a suitability for measuring low-power devices such as op amps, voltage references and voltage regulators. In addition, current injectors can be used to carry out other types of tests such as non-invasively measuring PSRR, determining power integrity and si

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