The Importance of Double Pulse Testing for Designing Today’s Power Converters

The field of power electronics is rapidly transitioning from the use of silicon semiconductor materials to wide bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN). One of the most common applications of GaN and SiC semiconductors is to enable smaller, faster and more efficient designs of power converters.

Power converters operate at multiple stages throughout the power delivery chain, and, because no conversion is 100% efficient, some power loss occurs at each step. A typical converter would have an efficiency of about 85% to 95%, meaning that 5% to 15% of the input power is dissipated within the converter, mostly as waste heat.

Wide Bandgap Device Test Solution

A significant portion of this loss is dissipated in switching devices such as MOSFETs. And the preferred test method to measure the switching parameters of MOSFETs is the “Double Pulse Test” method. The Tektronix’ Wide Bandgap Double Pulse Test Solution will be shown at World of Technology & Science (WoTS). The goal of the test is to accelerate validation around SiC and GaN power devices and systems with this full suite of instruments, software, probes and services.

Increase your system performance and lower your time-to-market with:

On-scope analysis conforming to JEDEC and IEC standards
1 GHz of bandwidth for easy analysis of fast-switching signals
Arbitrary Function Generator with built-in software for double pulse testing waveforms
High-side and Low-side probes offering common mode noise rejection and precise measurements
High-power power supplies for driving test circuits at realistic voltages and currents

The core of that solution is the Wide Bandgap Double Pulse Test application (Opt. WBG-DPT) which runs on the 5 Series B MSO oscilloscope. (It is also available on the 4 Series and 6 Series MSOs.) Here’s a brief look at the simplicity that solution brings.

Test Automation for MOSFET Device Characteristics

The demonstration at WoTS focused on measuring the switching characteristics on the high-side MOSFET and the reverse recovery on the low side. The double pulse testing application automates switching, timing, and diode reverse recovery measurements. A Tektronix High Voltage Differential THDP probe on the low side measures the voltage while an IsoVu™ TIVP probe measures the current.

Other elements of the demonstration system were a Tektronix AFG31000 Arbitrary Waveform Generator to generate the pulse to turn on the MOSFETs, a Keithley 2470 Source Measure Unit to generate the high voltage for the V_DS. And for powering the gate drivers a Keithley 2280S Precision Power Supply was used.