PD1500A Series Dynamic Power Device Analyzer/Double-Pulse Tester

Introduction

Power converters are a key component enabling the electrification of the transportation, renewable energy and industrial markets. To facilitate needed advances in power converter design, new wide-bandgap (WBG) semiconductor technologies, based on silicon carbide (SiC) and gallium nitride (GaN), are being commercialized. WBG semiconductors provide major leaps in speed (10x to 100x faster than older designs), higher voltage and thermal operation, which in turn improve efficiency, reduce size and cost.

However, the resulting high-performance power converters are proving difficult to design due to many new challenges when characterizing WBG semiconductors. These difficulties delay the innovation of semiconductor manufacturers and engineers designing new converters.

Homegrown test systems have been the primary source for characterizing WBG semiconductors. Building these systems has been necessary because, to date, commercially available test systems have not been readily available. Unfortunately, it is difficult to produce repeatable and reliable measurement results with one-off, “homegrown” testers. Unreliable results create additional obstacles for power-converter designers when correlating their measurements with the semiconductor’s data sheets.

To enable consistent, reliable characterization of WBG semiconductors, Keysight created the PD1500A dynamic power device analyzer platform. Initially employing the Double Pulse Test (DPT) technique, it has been developed in close collaboration with semiconductor manufacturers and designers from the energy and electric vehicle (EV) industries.

Reduce your time to market with the PD1500A

As an off-the-shelf measurement solution, the PD1500A delivers repeatable, reliable measurements of WBG semiconductors. The platform also ensures user safety and protection of the system’s measurement hardware.

The ability to ensure repeatable DPT results is built on Keysight’s expertise in measurement science. Examples include innovations in high-frequency testing (gigahertz range), low leakage (femto-ampere range), and pulsed power (1,500 A current, 10 μs resolution). As a result, Keysight is uniquely positioned to help you overcome the challenges of dynamic power-semiconductor characterization.

Included with the PD1500A are standard measurement techniques such as probe compensation, gain/offset adjustment, de-skewing, and common mode noise rejection. These techniques are utilized within an innovative measurement topology and layout. A semi-automated calibration routine (AutoCal) that corrects for system gain and offset errors was specifically developed for this system. The system also uses advanced techniques to compensate for inconsistencies when measuring current.

Overview: Established and emerging measurement methods

Fully characterizing a SiC- or GaN-based WBG device requires both static and dynamic measurements. Keysight’s B1505A and B1506A power device analyzers excel at static measurements. The PD1500A has the needed flexibility to address a variety of dynamic measurements and the evolution of JEDEC standards as they take shape.

Static measurements: The following parameters are typically used to understand the static characteristics of a power device:

• Output characteristics
• On-resistance
• Threshold voltage
• Transconductance
• Junction, input, output and reverse transfer capacitance
• Breakdown voltage
• Gate charge

Dynamic power converter design challenges

Semiconductor and power engineering teams are in a tenuous position. The market forces them to quickly develop and ship reliable products, while needing to overcome changing technology, unreliable measurements in a hazardous test environment. In the absence of commercial characterization solutions, most engineering teams have been forced to develop their own solutions. Some of their key challenges are listed below:

• Improving efficiency has resulted in higher frequency switching converters. Accounting for the high-frequency energy is important in both characterizing power semiconductors and in modeling and simulating them in power converter designs. This additional complication challenges the traditional power designer.
• The combination of increased frequency and higher power affects the reliability of the measurements. It is often hard to distinguish whether the measured signal is the device characteristic or the parasitic characteristic of the measurement setup.
• Operating with greater voltage (> 1000 V) and current (> 100 A) levels leads to a more hazardous test environment. Design and test engineers need to use extra precaution when working with lethal power levels.
• The process for making WBG semiconductors is still maturing and is not as well studied as Si-based semiconductors. The resulting unproven reliability makes it difficult for many designers to commit to WBG devices for their designs. This isn’t stopping some designers from using these new devices for mission critical applications such as renewable energy and EV’s.
• Characterization and test standards are under development and will soon drive a common methodology for testing WBG devices.