A 175-to-350 V hard-switched boost converter was constructed using a high-voltage GaN high-electron-mobility transistor grown on SiC substrate. The high speed and low on-resistance of the wide-band-gap device enabled extremely fast switching transients and low losses, resulting in a high conversion efficiency of 97.8% with 300-W output power at 1 MHz. The maximum efficiency was 98.0% at 214-W output power, well exceeding the state of the art of Si-based converters at similar frequencies.

A 97.8% Efficient GaN HEMT Boost Converter With 300-W Output Power at 1 MHz

Enhanced performance of RF power modules is required in a next-generation information society. To satisfy these requirements, we designed a novel high-electron mobility transistor (HEMT) structure employing wider bandgap AlGaN for a channel layer, which we called AlGaN channel HEMT, and investigated it. The wider bandgap is more effective for higher voltage operation of HEMTs and contributes to the increase of output power in RF power modules. As a result, fabricated AlGaN channel HEMTs had much higher breakdown voltages than those of conventional GaN channel HEMTs with good pinchoff operation and sufficiently high drain current density without noticeable current collapse. Furthermore, specific on-state resistances of fabricated AlGaN channel HEMTs were competitive with the best values of reported GaN- and SiC-based devices with similar breakdown voltages. These results indicate that the proposed AlGaN channel HEMTs are very promising not only for an information-communication society but also in the power electronics field.

AlGaN Channel HEMT With Extremely High Breakdown Voltage

In the early 1990s, gallium nitride (GaN) was deemed an excellent, next generation, semiconductor material for high power/high frequency transistors based on the material parameters of bandgap, electron mobility, and saturated electron velocity (Figure 1). The lack of bulk GaN source material led to the need for GaN growth on mismatched substrates such as Si, SiC and sapphire, but fundamental material development controlled the pace of maturation of GaN technology for both electronic and optoelectronic applications [1]. The development of GaN for RF electronics was significantly aided by the intense development that occurred in the race to first production of blue and, eventually, white light-emitting diodes (LEDs). Ultimately, advancements in the growth of device-grade aluminum gallium nitride (AlGaN)/GaN

History of GaN: High-Power RF Gallium Nitride (GaN) from Infancy to Manufacturable Process and Beyond

A high-power amplifier using two 288-mm-periphery GaN HEMTs was demonstrated with all matching components inside the package When biased at 55 V, a power bandwidth of 33-36 GHz was obtained, with 550-W peak output, 125-dB associated gain and 66% drain efficiency at 345 GHz

An Internally-matched GaN HEMT Amplifier with 550-watt Peak Power at 3.5 GHz

We developed a kW-class AlGaN/GaN HEMT pallet amplifier operating at S-band. The pallet amplifier consists of an internally partial-matched AlGaN/GaN HEMT optimized for S-band on a copper base with soft PC boards. The developed pallet amplifier showed excellent performance, which is output power of over 800 W, high linear gain of 13.6dB and high efficiency of 52% over the wide frequency range of 2.9-3.3 GHz, operating at 65 V drain voltage with the pulsed condition at a duty of 10% and a pulse width of 200 musec. With 80 V drain voltage operation the peak power reached to 1 kW with 49.5% drain efficiency and 14.1 dB linear gain at 3.2 GHz. To the best of our knowledge, this is the highest power pallet amplifier ever reported for S-band.

A kW-class AlGaN/GaN HEMT pallet amplifier for S-band high power application

We have successfully developed a 500W AlGaN/GaN HEMT power amplifier with a frequency of 1.5GHz in L-Band, operating at 65V drain bias voltage. This amplifier consists of 4-chips of HEMT die developed for L-band frequency operation with push-pull configuration. The developed amplifier has an output power of 500W and a high linear gain of 17.8dB at the frequency of 1.5GHz under pulsed conditions at a duty of 10% with a pulse width of 100musec. To the best of our knowledge, this is the highest power ever reported for L-band GaN-related amplifier

Takashi Yamamoto

Papers

A 500W Push-Pull AlGaN/GaN HEMT Amplifier for L-Band High Power Application