IsoFast high speed GaN driver to boost bidirectional single stage designs
Navitas Semiconductor has added a dedicated driver to its 650V bidirectional gallium nitride (GaN) chip to enable more single stage power designs.
The IsoFast high speed driver operates over 1MHz with the 650 V bi-directional GaNFast transistors launched last year and now in production. The bidirectional chip has a merged drain structure, two gate controls, and a patented, integrated, active substrate clamp and can replace up to 4 transistor switches. However this requires a specialised driver.
The IsoFast devices are galvanically isolated with 4x higher transient immunity than existing drivers and up to 200 V/ns swing with no external negative bias supply required.
“You need a special driver that can control the two gates and handle high transient conditions with 5kV operation and 200V/ns,” said Dan Kinzer, co-founder and CTO of Navitas. “IsoFast is the first high speed isolate gate driver at over 1MHz and 5000V.”
Initial parts are the NV1702 (dual, independent-channel, digital, isolated bi-directional GaN gate driver) and NV1701 (half-bridge GaN digital isolator) in SOIC-16N and SOIC-14W packages.
This combination enables the transition from two-stage to single-stage topologies, particularly for EV charging (On-Board Chargers (OBC) and roadside), solar inverters, energy storage and motor drives, says Gene Sheridan, CEO and co-founder of Navitas.
Over 70% of today’s high-voltage power converters use a two-stage topology with an initial power-factor-correction (PFC) stage and a follow-on DC-DC stage with DC-link electrolytic capacitors. Innoscience and Renesas Electronics (through its acquisition of Transphorm) are also in production with bidirectional GaN devices.
“With Gan BDS applied to single stage converters this is all about to change,” said Sheridan. “The DC-link electrolytic capacitors disappear and we can exploit the high frequency to shrink the magnetics for a 30% reduction in size with 10% energy savings and 10% lower cost.”
An EV and solar micro-inverter manufacturer have already begun their implementation of single-stage BDS converters to improve efficiency, size, and cost in their systems.
The initial 650 V bi-directional GaNFast ICs include NV6427 (100 mΩ RSS(ON) typ.) and NV6428 (50 mΩ RSS(ON) typ) in thermally enhanced, top-side-cooled TOLT-16L (Transistor Outline Leaded Topside-cooled) packaging. The product family will be extended into lower RSS(ON) offerings in the future.
The bi-directional NV6427 and NV6428 GaNfast transistors are fully qualified and immediately available in mass-production quantities. Samples of the NV1701 and NV1702 IsoFast drivers are available now to qualified customers.
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