HEMT compound semiconductors allow for smaller smartphones
With the proliferation of rechargeable mobile devices such as smartphones, tablet devices and external battery packs in recent years (as evidenced by the 151.49 million or so customers of mobile carriers in Japan1), one key issue for users is battery size and charge time. Recharging inevitably generates heat in the battery, reducing charging efficiency. Improving charging efficiency leads to two key benefits: faster charging and smaller batteries.
HEMT2 is a compound semiconductor created by Fujitsu in 1980. It is a field-effect transistor (FET) where the compound semiconductor comprises at least two different elements (hence “compound”). It is employed in compact parabola antennas for mobile phone and satellite applications, and is also used extensively in critical IT infrastructure such as navigation systems and wideband radio access systems for satellite broadcast receivers, smartphones and GPS devices. An exciting new development is GaN-HEMT (gallium nitride HEMT), which can operate at higher voltages than conventional semiconductor materials.
1 Combined total for mobile phones, PHS and BWA devices as per Ministry of Internal Affairs and Communications press release Quarterly figures for telecommunications services—subscriber numbers and market share—Q1 2015 (to June 30)
2 High Electron Mobility Transistor, the breakthrough compound semiconductor invented by Takashi Mimura at Fujitsu Laboratories in 1980, typically made from GaAs (gallium arsenide) and InP (indium phosphide).
An half-size adaptor boasting high power supply efficiency and triple-speed charging
Fujitsu Laboratories is proud to announce the successful development of a new compact, rapid-charging AC adaptor for smartphones. The GaN-HEMT adaptor offers switch elements with lower dynamic resistance, so minimizing the current losses normally associated with fast turnaround and delivering better current output timing. The adaptor is about half the size of a standard adaptor unit and can fully recharge a mobile phone three times more quickly3 than a conventional charger can when connected to a standard household power outlet. At just 15.6 cc in volume, it is the smallest 12 W AC adaptor in existence. It also boasts an impressive power efficiency of 87%, making it officially the best AC adaptor in the world today.
The new high-efficiency adaptor minimizes power consumption, which in turn reduces CO2 emissions. Fujitsu Laboratories is continuing to refine the adaptor in terms of efficiency and external dimensions with a view to bringing it to market in FY2017. Applications of this technology for high-output circuits such as notebook computers are also under consideration.
3 Charging time may vary depending on the device being charged