5 June 2018

Transphorm’s HV GaN FETs used in Seasonic’s new high-efficiency 1.6kW PFC platform

© Semiconductor Today Magazine / Juno PublishiPicture: Disco’s DAL7440 KABRA laser saw.

Transphorm Inc of Goleta, near Santa Barbara, CA, USA — which designs and manufactures JEDEC- and AEC-Q101-qualified gallium nitride (GaN) semiconductors — says that its high-voltage (HV) GaN field-effect transistors (FETs) are being used by Seasonic Electronics Co of Taipei, Taiwan in its new 1600W bridgeless totem-pole power factor correction (PFC) platform. The 1600T is the power supply manufacturer’s highest performing PFC platform to date, at greater than 99% efficiency. Notably, the introduction of GaN delivers a 2% efficiency increase and 20% power density increase over Seasonic’s previous silicon-based platform.

The 1600T platform will be scaled and deployed in catalog products targeting the charger (e-scooters, industrial, etc), gaming, server and PC power markets.

“When researching semiconductor technologies that would enable us to reach world-leading efficiency levels, gallium nitride stood out as an attractive alternative to silicon,” says Seasonic’s director of R&D Paul Lin. “We knew the bridgeless totem-pole PFC was the topology we would use in our first high-voltage GaN power platform. So, we needed power semiconductors capable of successfully capitalizing on that topology,” he adds. “We wanted a GaN solution that could be backed by our standard warranty. We ultimately opted for Transphorm’s FETs within the 1600T given their proven performance and reliability that allowed us to meet those requirements.”

The 1600T platform employs Transphorm’s TP65H035WS device, a 650V GaN FET with an on-resistance (RDS(on)) of 35mΩ in a standard TO-247 package. The transistor achieves increased efficiency in hard-and soft-switched circuits, providing power systems engineers options when designing products. Further, the TP65H035WS pairs with commonly used gate drivers to simplify designs while controlling costs. Also, Transphorm claims that its GaN typically delivers greater headroom and noise immunity compared with other available GaN FETs. The TP65H035WS’ typical gate threshold is 4V with a maximum gate voltage of ±20V.

Given GaN’s relative newness in high-voltage applications, Transphorm offers in-depth field application support and hands-on training. Seasonic leveraged the firm’s experts to strengthen the design itself while speeding time to market. For example, Transphorm’s guidance helped Seasonic’s team ramp on use of a simple, low-cost digital signal processor (DSP) to control the totem-pole PFC. Transphorm also aided in the platform’s component selection and system layout, ensuring optimal GaN performance. Ultimately, the co-development directly impacted Seasonic’s ability to drive up thermal efficiency while increasing power output, says Transphorm.

Tags: Transphorm GaN-on-Si GaN HEMT Power electronics

Visit: www.transphormusa.com