Measure power semiconductor capacitances in real-world conditions

July 02, 2014 // By Graham Prophet
Agilent Technologies has introduced the first power device capacitance analyser that automatically characterises power device junction capacitances using real operating voltages.

With the increasing use of power devices fabricated from emerging materials such as SiC and GaN, switching power supplies are now operating at increasingly higher frequencies. As a result, accurate device capacitance characterisation is more important than ever. Agilent's B1507A Power Device Capacitance Analyser has the ability to accurately and automatically evaluate all input, output and reverse transfer power device capacitance at high bias voltages.

The B1507A provides a complete solution for measuring and evaluating all parameters for high-frequency switching power supplies. Measurement capabilities include three-terminal capacitances (Ciss, Coss and Crss) with high-voltage bias (±3 kV), gate resistance, and accurate leakage current and breakdown voltage by complementing curve-tracer-type test equipment that evaluates only coarse IV characteristics.

An intuitive graphical user interface makes it easy for even a novice user to automatically measure all capacitances under a wide range of operating voltages. Such capabilities make the B1507A ideal for helping power electronics circuit designers select the optimal devices for their power electronic circuits and for power electronics manufacturers maximising product value and performance by revealing detailed device characteristics.

“Power devices used in power electronics circuits play a critical role in meeting industry requirements for low power loss and high switching frequency,” said Masaki Yamamoto, general manager of Agilent’s Hachioji Semiconductor Test Division. “However, until now no suitable solution has existed for fully evaluating their capacitance over a wide range of operating voltages. The B1507A promises to fill this gap by providing complete capacitance evaluation for power devices in a reliable and automated manner.”

Features of the B1507A include:

- easy to use, fully automated measurement of transistor input, output and reverse transfer capacitances (Ciss, Coss, Crss, Cies, Coes, Cres) at high bias voltages, independent terminal capacitances (Cgs, Cgd, Cds, Cge, Cgc, Cce), and capacitances for normally-on devices, such as SiC JFET or GaN FET;

- internal gate resistance (Rg) measurement;

- continuous capacitance measurement as the gate voltage varies from negative