Transphorm demonstrates 97.5% efficient PFC power supply



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Transphorm announced at PCIM 2013 the implementation of a high efficiency off-line 1kW 48Vdc power supply that has demonstrated peak efficiency of 97.5 percent. The power supply design utilizes Transphorm's JEDEC-qualified GaN on silicon 600V high electron mobility transistors (HEMTs) to implement a 99-percent-efficiency totem pole power factor correction (PFC) front end, combined with a 98.6% efficiency LLC converter. A prototype circuit is on display at the PCIM Europe Conference and Exhibition that is underway this week in Nuremberg, Germany. Based on Transphorm's patented, high-performance EZ-GaNTM technology, the TPH3006PS HEMT combines low switching and conduction losses to reduce energy loss by 50 percent compared to conventional silicon-based power conversion designs. The TO-220-packaged GaN transistor features low on-state resistance (RDS(on)) of 150 milliohms (m?), low reverse-recovery charge (Qrr) of 54 nanocoulombs (nC) and high-frequency switching capability — all of which result in lower loss, more compact, lower cost systems. "Transphorm's GaN-based power supply design exceeds the best efficiency results possible with silicon by at least one percent," said Umesh Mishra, CEO of Transphorm, Inc. "And while recent advances in super junction silicon devices have reduced the output capacitance by 20 percent and the Qrr of the intrinsic body diode by 25 percent, these improvements lag far behind the effective Qrr of the new GaN transistors which reduce Qrr by 95 percent." Transphorm's proprietary EZ- GaN platform can reduce power system size, increase energy density and deliver high efficiencies across the grid. For manufacturers looking for a low-risk roadmap to the next generation of power conversion technology, EZ-GaN provides a cost-effective, customizable and easy-to-use solution ready for commercial scale. For approved customers, the TPH3006PS and TPH3006PD HEMT devices are available for sale at a price of $5.89 each in 1,000 quantities. The TPS3410PK and TPS3411PK diodes are priced at $2.06 and $1.38, respectively, also in 1,000-piece quantities. Transphorm