The landscape for power adapters used to power everyday electronic devices ranging from phones to laptops has changed considerably since the introduction of USB-PD specifications and through its evolution. While USB-PD ensures wide-ranging compatibility, the power adapter design becomes somewhat more challenging: now, the power adapter has to support a wide range of output voltages (as opposed to a single output voltage for captive use adapters). Meanwhile, the end user’s desire for lighter, smaller adapters continues. Gallium nitride power switches have been introduced in recent years to address these dual requirements.
GaN devices offer lower conduction and switching losses compared with silicon devices that enable higher switching-frequency operation at high efficiency, hence lighter and smaller adapters. GaN-device–based designs require special attention because the gate voltage range is limited and the gate is susceptible to spurious turn-on and turn-off. However, GaN FETs with monolithically integrated drivers such as the TP44x00NM series from Tagore Technology make the implementation robust and easy in addition to offering space savings.