IsoFast high speed GaN driver for bidirectional single stage designs

Navitas Semiconductor has introduced a dedicated driver to its 650V bidirectional gallium nitride (GaN) chip, enhancing the potential for single-stage power designs. The IsoFast high-speed driver, operating at over 1MHz, complements the 650V bi-directional GaNFast transistors that were launched last year and are currently in production. This bidirectional chip features a merged drain structure, two gate controls, and a patented integrated active substrate clamp, capable of replacing up to 4 transistor switches, albeit requiring a specialized driver.

The IsoFast devices offer galvanic isolation with 4 times higher transient immunity compared to existing drivers, along with up to 200 V/ns swing without the need for an external negative bias supply. Dan Kinzer, co-founder and CTO of Navitas, emphasized the necessity of a special driver that can effectively manage the two gates and handle high transient conditions with 5kV operation and 200V/ns. Kinzer highlighted that IsoFast represents the first high-speed isolate gate driver operating at over 1MHz and 5000V.

Navitas is rolling out initial parts such as 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. The company aims to expand its production in Europe and the US for GaN and SiC applications, particularly focusing on datacenter AI power.

This innovative combination facilitates the shift from two-stage to single-stage topologies, especially beneficial for applications like EV charging (On-Board Chargers and roadside), solar inverters, energy storage, and motor drives. Gene Sheridan, CEO and co-founder of Navitas, underlined the significance of this transition, highlighting the potential for efficiency improvements and cost savings in various systems.

Currently, a majority of high-voltage power converters utilize a two-stage topology with an initial power-factor-correction (PFC) stage followed by a DC-DC stage with DC-link electrolytic capacitors. However, with the advent of GaN BDS applied to single-stage converters, the landscape is set to transform. Sheridan pointed out that the disappearance of DC-link electrolytic capacitors and the ability to leverage high frequency for downsizing magnetics could lead to a 30% reduction in size, along with 10% energy savings and 10% lower costs.