Oscilloscope-based double pulse test speeds up validation time of SiC and GaN


Tektronix has updated its oscilloscope-based Double Pulse Test (WBG-DPT) for wide bandgap Silicon carbide and gallium nitride transistors.

The WBG-DPT update enables significant advances in electric vehicles, solar energy and industrial controls with automated, repeatable, and accurate measurements on SiC and GaN MOSFETs.

Designers of power converters will now be able to use WBG-DPT on Tektronix 4, 5 and 6 Series MSO oscilloscopes, integrating seamlessly into the measurement system. This has several industry-first measurement capabilities, such as an automatic WBG deskew technique and reverse recovery timing plots, making it easier for engineers to see reverse recovery details for multiple pulses overlaid on a single display. Measurements are also designed to align with JEDEC and IEC standards for double pulse testing and diode reverse recovery.

To achieve meaningful energy loss measurements, designers must correct for delays introduced by test fixtures and probes. The traditional technique for aligning drain-to-source- voltage (VDS) and drain current (ID) measurements requires rewiring the test setup and careful pretest measurements.

The WBG deskew technique eliminates the need for rewiring and may even be performed after double pulse measurements have been taken. To simulate the effects of delays in the test setup, the software generates an alignment waveform. The engineer adjusts a few settings to match the alignment waveform with the measured waveform, as the software corrects any differences in delays. This reduces the deskew time from an hour or more to just 5 to 10 minutes.

“The WBG-DPT software provides instantaneous measurements of key parameters, like EON, EOFF, and QRR when performing double-pulse tests,” said Masashi Nogawa, staff systems engineer at power chip designer Qorvo. “The software makes the power waveform and markers showing the integration ranges used to calculate the energy losses immediately visible. This is an excellent alternative to exporting waveform data into Excel spreadsheets for processing.”

As power converters must operate over a wide range of temperature conditions, there is a growing need to measure output charge (QOSS) at different junction temperatures. WBG-DPT provides fast and accurate QOSS measurements, providing important insight into the effects of device output capacitance.

The reverse recovery timing plots make it easy for engineers to see reverse recovery details for multiple pulses overlaid on a single display. Measurements are made per JEDEC and IEC standards, and users can configure measurements in WBG solution to query results on every first or second pulse, or all pulses of a double pulse set. This unique approach to reverse recovery plotting allows for multiple double pulse sets and provides visual and measurement results on each set. The measurement provides the ability to easily zoom in on the reverse recovery region and even debug reverse recovery parameters of the system.

“Tektronix customers are the designers of the next generation of cutting-edge power electronics technology, and their designs must be optimized to balance efficiency, size and reliability,” said Daryl Ellis, Tektronix Mainstream Portfolio General Manager.

“We are confident that the design of the Tektronix WBG-DPT Solution will allow for simplified debugging, repeatable measurements (per JEDEC and IEC standards) and a faster learning curve. Test automation reduces test times and retesting errors, ensuring our customers meet their project timelines and time to market plans,” he said.

The Tektronix Wide Bandgap Double Pulse Test solution is now available, contact us for more information.