Ensuring Optimal Performance of your Power Supply Design

Wednesday, August 21, 2019 作者： Tektronix Expert

Are you working on power circuit stability?
Are your DC-DC converters performing as expected?
Are you having trouble optimizing your power conversion circuits?
Are you having trouble getting the promised efficiency and performance from your fast switching power converter?

Current power supply topologies are reliable and well understood in the power electronics industry. New wide bandgap semiconductors like SiC and GaN are poised to play a bigger role in power convertor applications but require fine tuning designs that may be reaching their limits. Increasing need for efficiency with growing power circuit density is being pushed from industries such as automotive, data-centers, renewable systems, consumer electronics, and industrial power electronics, are creating new test and measurement challenges in power stability.

Power designers typically perform Control Loop Response (CLR) analysis and Power Supply Rejection Ratio (PSRR) measurements to ensure the stability of feedback path of the control loop. Solving these challenges is tough for engineers. They typically need a standalone Frequency Response Analyzer or VNA to get critical insights to the signal behavior.

However, there may be better solutions in the market used by every power engineer which is, go-to resource for power supply measurement and analysis – that is, the oscilloscope.

Tektronix has created a kit solution that uses the 5 Series or 6 Series MSOs to give a single box solution for power supply measurement and analysis. The kit provides everything required to accurately test Control loop Response and PSRR – in addition to switching loss, inductor and transformer loss, and safe operation area (SOA).

Tektronix Control Loop Response Analysis kit comes equipped with powerful 5/6-PWR software which enables testing switching loss, conduction loss, magnetic property, input and output power quality measurements, and overall power/system efficiency.

Frequently Asked Questions (FAQs)

You mentioned “FRA.” What does that mean?

FRA stands for Frequency Response Analysis. This is the suite of measurements that is a part of the 5/6-PWR software that runs on the 5 and 6 Series MSO. The software/hardware combo helps you measure:

Control Loop Response measurement or popularly known as BODE plot is a measure of Gain and Phase performance over a band of frequencies.
Power Supply Rejection Ratio (PSRR) is a measure of how good a Power Converter design is in terms of the output ripple component that it filters out over a band of frequencies.

Are there upgrade options or expansion options?

The MSO5/6 scope is compatible with all modern Tektronix probes and can be upgraded and updated for other applications. See details on the MSO5/6 product page .

5/6-PWR software can be upgraded to add features on a later date.

Are the pieces compatible with other Tek probes/scopes?

The MSO5/6 scope is compatible with all modern Tektronix probes.

How were all the parts in the kit chosen?

5/6 Series MSO Oscilloscope is a high resolution (12 bit) oscilloscope ideal for testing Power designs. The 5 Series MSO has 8 channels for you to see and measure more timing signals at the same time to optimize your performance. We recommend the 5 Series MSO with built in AFG option to make this a complete one box solution.
5/6-PWR software is designed to run automated, accurate, and repeatable power measurements for calculating switching loss, conduction loss, RDS_ON, magnetic property, SOA, and more under in-circuit operation. The FRA measurement option is included in the 5/6 PWR software option.
TPP0502 probes are ideal choice for FRA measurements due to their low input capacitance.
TPP1000 is a 1GHz high bandwidth passive probe that comes as standard equipment with the MSO5 oscilloscope, with one probe per channel. This probe is ideal for testing ground referenced high dv/dt signals such as VGS_lo/VDS_lo and shunt voltages.
Picotest Isolation and Injection transformers are recommended third party accessories that are needed for FRA measurements.

Do I need special test points on my board to measure Bode and PSSR?

Yes, you need to have provision for injecting the stimulus signal in the feedback loop and typically a low resistance value (5/10 Ohm) injection resistor is needed to be added to the circuit.

Can I configure the kit?

Depending on your application and switching speeds, you can configure the kit for the appropriate bandwidth and number of measurement channels needed.

What is the amplitude profile and when should I use it?

FRA measurements provide 2 amplitude settings – constant and profile. With amplitude profiling, one can test at lower amplitudes at frequencies where the DUT is sensitive, and test at higher amplitudes where it is less sensitive to distortion. Adjust the amplitudes based on the signal from the DUT. One can run a few tests at different frequencies to determine an optimized amplitude profile.

Double pulse testing (requires other products)
Bulk current injection
ESD testing
Differential voltage testing in EMI/EMC applications
Any differential measurement application within specifications

I have never used this equipment before. Can you help?

We have created a “Getting Started Instruction Guide” with instructions to get you started.

We also have a series of “How to videos” to help with setup and debugging problems.

What is my incentive in buying this kit versus individual parts?

The kit gives you everything you need for this application.
You will get all the instructions to get started and reduce your learning curve.
All parts are guaranteed to work together for this application.
It will make it easy for you to order all at once.