GaN HEMT – Gallium Nitride Transistor
CoolGaN™ - the new power paradigm
Gallium nitride (GaN) offers fundamental advantages over silicon. In particular, the higher critical electrical field makes it very attractive for power semiconductor devices with outstanding specific dynamic on-state resistance and smaller capacitances compared to silicon MOSFETs, which makes GaN HEMTs great for high speed switching. Not only because of the resulting power savings and total system cost reduction, it also allows a higher operating frequency, improves the power density as well as the overall system efficiency.
The most important feature of a GaN power transistor is its reverse recovery performance. As Infineon’s CoolGaN™ transistors have no minority carriers and no body diode they do not exhibit a reverse recovery, which makes them well-suited for half-bridge topologies.
Gallium nitride CoolGaN™ e-mode HEMTs in the applications
Infineon's gallium nitride CoolGaN™ family adds significant value to a broad variety of systems across many applications. These e-mode HEMTs target consumer and industrial applications such as server, datacom, telecom, adapter/charger, wireless charging and audio with the most robust and performing concept in the market.
Using Infineon’s CoolGaN™ in high-power applications such as server power supply and telecom applications, leads to cost savings and more power per rack. It also allows for easier control schemes due to its hard-switching capabilities, while at the same time offering efficiency benefits compared to the next best silicon alternative.
Gallium nitride technology in adapter and charger power supplies is a breakthrough in power density for small and lightweight, highly efficient solutions. Using Infineon’s CoolGaN™ in wireless power transfer enables high efficiency at higher power levels as well as optimal tuning in class E designs.
CoolGaN™ 400V devices in class D audio maximize audio performance for an excellent sound quality. Furthermore, there are almost no thermal design limitations, it is very easy to use and compatible with Infineon’s MERUS ™ class D audio amplifiers.
By implementing gallium nitride CoolGaN™ e-mode HEMTs in a totem pole PFC combined with a LLC DC-DC stage, >98.5% system efficiency can be achieved (for 48V output voltage systems) providing a total of 2 billion kWh annual savings for US data centers (~ 300 million USD annual savings @ 0.15 USD/kWh).
GaN based SMPS solutions enable more compute power per rack by pushing the power density to >80W/in3 from today’s typical ~30..40 W/in3 of silicon based solutions.
Operating expense (OPEX) and capital expenditure (CAPEX) savings, overall reduction of power supply footprint and highest solution robustness have been and will remain in the focus of telecommunication infrastructure development. Infineon’s gallium nitride CoolGaN™ solution addresses these challenges by providing benchmark efficiency in the entire operation range, maximizing power density while following Infineon’s stringent qualification regime.
Adapter and charger
Infineon’s CoolGaN™ is a breakthrough for adapter and charger systems, enabling ~20W/in3 power density (for 65W maximum output power). This advantage can be realized by implementing CoolGaN™ in a half-bridge topology that enables increased switching frequency and efficiency simultaneously.
Gallium Nitride CoolGaN™ emode HEMTs enable optimal tuning in class E amplifiers especially above 30W, and offers major advantages over silicon in 6.78MHz wireless charging.
- Low almost linear COSS without large increase at low VDS enables ZVS operation over wide load impedance range
- Very low QG compared to equivalent silicon MOSFET
- 5V gate drive, very low gate drive losses
- Robust devices – self clamping gate instead of Schottky gate structure
Class D audio amplifier
Infineon’s CoolGaN™ 400V e-mode HEMTs allow approaching the theoretical ideal performance of class D audio amplifiers. Due to its unique characteristics, perfectly suited for this application: zero reverse recovery charge (QRR) of the body diode, linear input and output capacitances, and extremely fast switching speeds (lowest QGD and RG) result in ideal switching waveforms, close to an ideal switch. These ideal switching waveforms are the prerequisite to maximize audio performance and minimize power losses in class D audio amplifier.