Software turns scopes into power analysers

Tektronix has an automated measurement software package it reckons will dramatically enhance the efficiency of power measurements made with its oscilloscopes.

Tektronix has an automated measurement software package it reckons will dramatically enhance the efficiency of power measurements made with its oscilloscopes.

Two trends, the use of fast, low-voltage devices in digital systems and the rapidly expanding array of portable electronic devices, are driving the demand for compact, low-cost switch-mode power supplies.

The design of these supplies relies on accurate analysis of parameters such as switching loss, magnetic flux density (B-H) analysis, and safe operating area within the supply.

The Tektronix TDSPWR2 power measurement and analysis software package brings automated power measurements and documentation features to Tektronix' proven TDS5000 Series, the TDS7054, and the TDS7104 digital phosphor oscilloscopes (DPOs).

The package allows engineers to easily perform critical power measurements (including precompliance tests to EN61000-3-2 standards) and bring their new designs to market quickly.

"Tektronix has a history of enabling industry advancements with easy-to-use and affordable solutions that leverage the power of its successful oscilloscope platform", said Colin Shepard, Vice President, Oscilloscope Products, Tektronix, "The new TDSPWR2 software package transforms the DPO into an integrated power analysis tool, using the DPO's exceptional waveform capture rate, probing capabilities, and other features to produce a solution that will simplify the discipline of power supply design".

Digital system operating rates continue to escalate, a trend enabled in part by reducing the operating voltages of semiconductor components such as processors and memory devices.

Today's emerging IC devices operate at only half the voltage (2.5V) of components in common use just a few years ago.

To ensure that these critical voltage levels stay within allowable margins, the ICs need distributed power sources placed close to the point of use.

Distributed power supplies must be small, efficient, and low in cost.

Because the supplies use high frequency internally, often without heatsinks, they must ensure low power dissipation and reliable operation.

Designers must analyse power supply switching waveforms, measure power losses at various points, determine the safe operating area (SOA), and more.

In addition, they must prepare for rigorous compliance tests to EN61000-3-2 standards and document their results in detail, all under the usual constraints of time-to-market and competitive quality pressure.

The TDSPWR2 application package answers all of these needs, integrating a host of automated measurement, display, and analysis features into the TDS5000 Series' three models, the TDS7054, and the TDS7104 DPOs.

All these instruments offer high bandwidth, ample record length, and high waveform capture rate.

Additionally, they are compatible with Tektronix' broad selection of industry leading current and differential probes via the intelligent TekProbe interface.

Adding TDSPWR2 software to any of the listed DPO models makes the instrument into a full-featured power supply measurement tool for switch-mode power supplies.

When TDSPWR2 is running, the screen display brings up a set of soft buttons and readouts optimised for the task.

Automated measurements of switching device power losses and inductor/transformer core losses help designers quickly summarise total power loss.

"High power finder" and "switching finder" tools rapidly locate areas of high power dissipation, while the one-button "ripple finder" automates time-consuming ripple tests.

The safe operating area, too, is automatically determined; the oscilloscope allocates an appropriate amount record length to capture the full duration of the event of interest.

Engineers can use cursors to zoom in on anomalies for troubleshooting.

The worldwide EN61000-3-2 standard requires detailed analysis of the harmonic content of the current waveform at the input of power supply.

The TDSPWR2 application package includes an automated series of tests that allow designers to confirm, in advance, that their power supply conforms to the standard.

These pre-compliance tests forestall time-consuming repetitions of the final compliance test cycle, which requires costly specialised equipment.

Equally important, the TDSPWR2 package's automated precompliance tests free the engineer from the need to study and learn the complexities of the EN61000-3-2 test procedures.

Documentation is uniquely important in the power supply design process.

Makers of power supplies sell their products to computer and communications equipment manufacturers, who insist on thorough documentation to prove that design guidelines have been met.

This documentation may extend to hundreds of pages and screen images software, which installs into the oscilloscopes' built-in Windows environment, implements reports in any user-configured format.

In addition, measurement findings can be exported to analysis applications such as Excel and MathCAD, all within the oscilloscope itself, and results can be emailed directly from the instrument to end users.

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