LTSpice Model Simplifies Designing With GaN

GaN Systems has introduced a new set of LTSpice models designed so that power system designers can get the benefits of GaN transistors and optimise system performance. The tool is said to provide a convenient and accurate way to understand GaN switching characteristics, evaluate GaN switching performance under different electrical conditions and build overall confidence in a new product design.
“Rarely do designers use spice simulation to estimate Eon/Eoff; with our models they can. We expect that this tool will help designers more fully understand GaN technology and accelerate their design completion,” aid Larry Spaziani,GaN Systems VP of sales and marketing.

The LTSpice model user guide helps engineers model systems at three levels, ranging from an initial overview of circuit performance to detailed analysis and fine tuning of the design:

Level 1: Basic adjustment and analysis of switching speeds, optimised for quick simulation.

Level 2: In additional to Level 1 features, includes thermal inputs and Cauer thermal RC network transient models for simulating the device junction temperature and self-heating effect.

Level 3: In addition to Level 2 features, includes parasitic losses, provides the most accurate model with longest simulation times.

To confirm the accuracy of the LTSpice model, laboratory measurements of GaN E-HEMT switching losses were recorded using a half-bridge, double-pulse test circuit. The switching losses measured in the test were then compared with the LTSpice model simulations. The comparison demonstrates a strong correlation between the simulated results and real-time circuit measurements. With a 400 V, 0 to 30 A switching current setup using a 650 V, 50 milliohm GS65008T device, the difference between actual measurement and the simulated model is less than 5 percent, a very good number for Eon/Eoff accuracy.