18 March 2020
Transphorm’s GaN FETs used in HZZH’s 98%-efficient power module
Transphorm Inc of Goleta, near Santa Barbara, CA, USA — which designs and manufactures JEDEC- and AEC-Q101-qualified high-voltage gallium nitride (GaN) field-effect transistors (FETs) — says that Hangzhou Zhongheng Electric Co Ltd (HZZH) has developed an ultra-efficient, GaN-based power module. The 3kW ZHR483KS uses Transphorm’s GaN devices to reach 98% efficiency, making it the telecoms industry’s most efficient GaN-powered module to date, it is reckoned. Original design manufacturers (ODMs) can swap the ZHR483KS — which offers standardized output connector configurations — with existing same-wattage power modules to achieve a high-reliability, higher-performing solution at a lower overall system cost.
Currently in production, the ZHR483KS is HZZH’s first GaN-based power solution and is the flagship product for a new product line. The module’s input voltage ranges from 85V to 264V, while its output voltage ranges from 42V to 58V. Transphorm’s TPH3205WS GaN devices are used in an interleaved bridgeless totem-pole PFC to achieve 98% efficiency at half load. The GaN devices lower the power module’s switching and driving losses, leading to the ZHR483KS outperforming preceding modules that used superjunction silicon MOSFETs.
“We sought a power transistor that would enable us to develop a more efficient yet cost-effective solution for our customers,” says HZZH’s chief technology officer Dr Guo. “We considered silicon carbide devices but could not achieve the desired advantages at low voltages,” he adds. “We then vetted several GaN manufacturers’ devices, and ultimately selected Transphorm’s GaN FETs due to their reliability, device cost, and simple implementation.”
Transphorm’s GaN FETs are two-chip normally-off devices available in standard TO-XXX packages and PQFN modules that can be driven with common off-the-shelf drivers. The existing Gen III family offers what is claimed to be the GaN semiconductor industry’s highest threshold voltage at 4V and highest gate robustness at ±20V. These features enable customers to easily design in highly reliable GaN solutions to gain the technology’s high-power density benefits.
“Transphorm develops each generation of its GaN platform with four key factors in mind: reliability, drivability, designability, and reproducibility,” says Kenny Yim, VP of Asia sales. “We’re proud that HZZH selected us as its GaN partner as it affirms that those four factors are what our customers need to disrupt their markets. They result in our GaN being designed into a wide range of multi-kilowatt power systems that are setting industry records,” he adds. “We anticipate HZZH will continue to innovate as our collaboration continues on future products.”
Transphorm GaN-on-Si GaN HEMT Power electronics