Complex circuit simulation and nonlinear characteristics analysis of GaN power switching device

Abstract

To overcome the problem of energy losses in the electrical circuits and to improve the energy conversion efficiency, it is necessary to increase the power switch frequency and reduce the open resistance of the power switch. Moreover, based on energy saving, failure protection, circuit design and other aspects of the research of enhanced devices are also essential, a new static and dynamic model of GaN power transistor is proposed, and the steady-state and dynamic characteristics of GaN power transistors are simulated and tested. The GaN power transistor used in the test has a constant voltage of 450 V and a current of 4 A. By changing the driving power U, G (take 2, 3, 4V) and the stray inductance Ls (take 2 μH, 5 μH), the switching characteristics of the simulation model were studied, and the simulation was carried out by changing the absorption capacitance Cc (select 1.5 μF and 3.0 μF). This proposed simulation model can be used to analyze the protection effect of the buffer circuit under various stray inductors and help to guide the design of the buffer circuit. The simulation results of the static and dynamic models of the new GaN power transistor agree well with the experimental results. With the increase of Ug, the opening speed is faster, but the turn-off delay is longer. With the increase of Ls, the peak of the turn-off voltage increases. After increasing the absorption capacitance, the peak voltage during the turnoff is limited to the rated voltage, and the buffer circuit plays a protective role and the greater the Cc, the better the protection. The simulation results are consistent with the theoretical analysis, which verifies the effectiveness of the model.

Keywords

• gallium nitride
• power transistor
• complex circuit simulation