Microwave-acoustic-based isolated gate driver for power electronics

TL;DR

This paper introduces a microwave-frequency surface acoustic wave (SAW) device on lithium niobate that provides galvanic isolation and enables high-performance, compact isolated gate driving for power electronics, operating over a wide temperature range.

Contribution

The authors demonstrate a mechanically-isolated gate driver based on microwave SAW technology that achieves high voltage isolation, low capacitance, and fast switching suitable for advanced power electronics.

Findings

Achieved galvanic isolation of 2.75 kV with ultralow capacitance (0.032 pF).

Delivered 13.4 V open-circuit voltage and 44.4 mA short-circuit current.

Validated operation in a buck converter with a GaN transistor, with a turn-on time of 108.8 ns.

Abstract

Electrical isolation is critical to ensure safety and minimize electromagnetic interference (EMI), yet existing methods struggle to simultaneously transmit power and signals through a unified channel. Here we demonstrate a mechanically-isolated gate driver based on microwave-frequency surface acoustic wave (SAW) device on lithium niobate that achieves galvanic isolation of 2.75 kV with ultralow isolation capacitance (0.032 pF) over 1.25 mm mechanical propagation length, delivering 13.4 V open-circuit voltage and 44.4 mA short-circuit current. We demonstrate isolated gate driving for a gallium nitride (GaN) high-electron-mobility transistor, achieving a turn-on time of 108.8 ns comparable to commercial drivers and validate its operation in a buck converter. In addition, our SAW device operates over an ultrawide temperature range from 0.5 K (-272.6 {\deg}C) to 544 K (271 {\deg}C). The microwave-frequency SAW devices offer inherent EMI immunity and potential for heterogeneous integration on multiple semiconductor platforms, enabling compact, high-performance isolated power and signal transmission in advanced power electronics.