The reference design uses the LMG3100R017, a small-size GaN field-effect transistor (FET), for a three-phase inverter. The LMG3100R017 integrates the driver and 80V GaN FET in a 6.5mm × 4mm QFN package. This package is optimized for extremely low gate loop and power loop impedance. The PCB offers mounting holes for a heat sink with the top-side cooled LMG3100R017 GaN-FET power modules. An integrated bootstrap diode reduces space for the high-side GaN-FET bias supply.

The control uses the UCD3138A, a digital power supply controller from Texas Instruments. The UCD3138A offers excellent levels of integration and performance in a single-chip solution. The UCD3138A has PMBus communication, which enables easy firmware upgrade and reporting. The design monitors each phase input current through a bi-directional current sense amplifier, the INA241. The reference uses the TLV431 to enable bidirectional current measurement for both buck and boost operation. The 5V auxiliary supply uses an integrated buck module, the TPSM365R6, followed by a low-dropout (LDO) linear regulator to generate a 3.3V rail.

Figure 2-1 System Block Diagram