Transphorm Inc of Goleta, near Santa Barbara, CA, USA, which designs and manufactures what it claims are the industry’s only JEDEC-qualified 650V gallium nitride (GaN) field-effect transistors (FETs) for high-voltage power conversion applications, says that its second-generation JEDEC-qualified high-voltage gallium nitride (GaN) technology is now the industry’s first GaN solution to earn automotive qualification, having passed the Automotive Electronics Council’s AEC-Q101 stress tests for automotive-grade discrete semiconductors.
In production now and available for $13.89 in 1000-unit quantities, the TPH3205WSBQA automotive GaN FET offers an on-resistance of 49mΩ in an industry-standard TO-247 package. It initially targets on-board charger (OBC) and DC-to-DC systems for plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEV). Currently, OBCs are uni-directional (AC to DC) using standard boost topologies. However, as GaN FETs are bi-directional by nature, they are a fit for the bridgeless totem-pole power factor correction (PFC) topology. Hence, a bi-directional OBC can then be designed with GaN in order to reduce the number of silicon devices, weight and overall system cost of existing solutions.
“With the electrification of the automobile, the industry faces new system size, weight, performance and cost challenges that can be addressed by GaN,” says Philip Zuk, senior director of technical marketing. “However, supplying this market means devices must meet the highest possible standards for quality and reliability, those set by the AEC,” he adds.
Transphorm says that its quality and reliability (Q+R) culture feeds into every aspect of its GaN-on-Si products. The firm is vertically integrated through the whole design and development cycle — innovating at the epi layer, adapting the fab process to the product, configuring the device and developing customer design tools and resources — enabling it to deliver what is claimed to be the industry’s only GaN devices with proven quality, reliability and intrinsic lifetime data extending beyond JEDEC requirements.
Transphorm says that Q+R played a critical role in achieving AEC-Q101 qualification. The firm’s GaN technology was subjected to a series of rigorous tests including parametric verification, high-temperature reverse bias and high-temperature gate bias. Devices receive a simple pass/fail rating and must pass all modules to become qualified.
The automotive market is one of the fastest-growing segments for all power semiconductors and will rise to $3bn in annual revenue by 2022, forecasts analyst firm IHS Markit. Due to its inherent attributes, Transphorm’s GaN can support a large portion of the market. Compared with incumbent technology such as superjunction MOSFETs, insulated-gate bipolar transistors (IGBTs) and silicon carbide (SiC), those attributes include: up to 40% greater power density; increased efficiency; lower thermal budget; reduced system weight; up to 20% decrease in overall system cost; and high-volume manufacturing with 6-inch GaN-on-silicon. As a result, Transphorm’s GaN also can be used in other high-voltage DC-to-DC automotive systems including air conditioning, heating, oil pumps and power steering.
