Half-bridge HEMT GaN devices simplify power-supply designs

STMicroelectronics’ MasterGaN1L and MasterGaN4L introduce the next generation of integrated gallium-nitride (GaN) bridge devices that simplify power-supply design leveraging wide-bandgap technology to achieve the latest ecodesign targets.

ST’s MasterGaN family combines 650V GaN high electron-mobility transistors (HEMT) with optimized gate drivers, system protection, and an integrated bootstrap diode that helps power the device at startup. Integrating these features saves designers tackling the complex gate-drive requirements of GaN transistors. Housed in a compact power package, the devices also enhance reliability, cut the bill of materials, and ease circuit layout.

The latest devices contain two GaN HEMTs connected in a half-bridge configuration. The arrangement is suitable for building switched-mode power supplies, adapters, and chargers with active-clamp flyback, active-clamp forward, and resonant converter topologies. The MasterGaN1L and MasterGaN4L are pin-compatible with MasterGaN1 and MasterGaN4 respectively. Compared to the earlier devices, they have a newly optimized turn-on delay that allows working at higher frequency and higher efficiency with low load, especially in resonant topologies.

The inputs accept signal voltages from 3.3V to 15V, with hysteresis and pull-down that facilitate connecting directly to a controlling device such as a microcontroller, DSP, or Hall-effect sensors. A dedicated shutdown pin helps designers save system power and the two GaN HEMTs have accurately matched timing with an interlocking circuit to prevent cross-conduction conditions.

The MasterGaN1L HEMTs have 150mΩ RDS(on) and 10A rated current, for use in applications up to 500W. Consuming just 20mW of no-load power, and enabling high conversion efficiency, they enable designers to meet stringent industry targets for standby power and average efficiency. The MasterGaN4L HEMTs target applications up to 200W, with 225mΩ RDS(on) and a rated current of 6.5A.

The EVLMG1LPBRDR1 and EVLMG4LPWRBR1 demonstration boards are available to help evaluate the features of each device. These boards contain a GaN-based half-bridge power module fine-tuned to work in an LLC application. They help quickly create new topologies leveraging the MasterGaN1L and MasterGaN4L devices without needing a complete PCB design.

Both devices are in production now in 9mm x 9mm x 1mm GQFN, priced from $4.40 for MasterGaN1L and $3.78 for MasterGaN4L.