A transistor is a small electronic switch that opens and closes very quickly, and GaN has several advantages over silicon when used in transistors. GaN transistors are not only smaller than silicon transistors, they can also carry more power, switch faster (about 40 million times a second, about four times faster than silicon transistors), and are much more energy efficient.
While silicon transistors have an energy efficiency of about 87%, GaN transistors can increase this efficiency to over 95%.
The reduction in transistor size means that newer GaN USB chargers can be physically smaller than older silicon-based chargers. And while having a smaller charger is nice, increased efficiency is the most important factor when it comes to USB chargers, as the more efficient the electronics, the less heat they generate.
Consumers are understandably concerned about chargers that are hot to the touch. While chargers that use silicon transistors often get so hot that they’re almost untouchable, I’ve rarely seen chargers that use GaN technology get even slightly warm.
Faster switching also means that the GaN transistors inside the charger can better control the charging process and react to events like overheating or overvoltage much faster than older transistors, making them safer to use.
