A Three-Phase GaN-on-Si Inverter IC for Low-Voltage Motor Drives

A GaN-based monolithic three-phase inverter IC is presented. The high-side and low-side transistors are intrinsically interleaved in each phase for low area-specific on-resistance and strong thermal coupling. Electrically, the effect of capacitive substrate coupling is investigated for SVPWM. A substrate biasing network for semi-floating substrate termination of the three-phase IC is proposed to minimize negative back-gating. Thermally, a low 5.6 micrometer pitch between the interleaved high-/low-side transistor fingers, and 625 micrometer phase-to-phase pitch reduces the temperature ripple at the kHz-range (from switching) and Hz-range (from phase-shifted currents) compared to discrete transistors.