Electric vehicles are increasingly driving on our roads, the majority of them are powered by a battery (BEV) and only a few models by a fuel-cell. The foreseeable future for passenger vehicles is in BEVs and for trucks perhaps in hydrogen-driven fuel cells, since trucks have to run for long distances without long charging stops. Nevertheless, both types of drive trains operate at increasingly higher voltage levels in order to decrease power losses (well-to-wheel), whereas this figure is around 70 % for fuel-cell vehicled and 30 % for BEVs. And for BEVs another point is important – the range and associated range anxiety as well as the charging time. The higher the DC charging power the lower the charging time – and the higher the charging voltage at a given current the higher the power according to P = V x I!

“The future of BEVs is above 1000 volts”, expects Peter Vaughan, Director of Automotive Business Development at Power Integration in Santa Clara. “Battery voltage levels of 900 volts are already common in electric vehicles such as the Lucid Air, generating only 20 percent of the heat losses compared to a 400-V sytem. Thus automakers are looking at 1000 and 1200 volts as the next step! And here 1700 V power switches and particularly Silicon Carbide MOSFETs come into play.”

On February 1, 2022, the company announced with its second SiC attempt two AEC-Q100 qualified, 1700-V rated ICs to its InnoSwitch™3-AQ family. The devices are the industry’s first automotive-qualified switching power supply co-packaged ICs to incorporate a primary switching SiC MOSFET. Delivering up to 70 watts of output power, the new ICs are targeted for use in 600- and 800-V battery and fuel-cell electric passenger vehicles, as well as electric buses, trucks and a wide range of industrial power applications.

InnoSwitch ICs reduce the number of components required to implement a Flyback power supply by as much as 50 %, saving significant circuit-board space, enhancing system reliability and mitigating component sourcing challenges. Synchronous rectification and a quasi-resonant (QR) / CCM flyback controller achieves greater than 90 % efficiency. These new parts consume less than 15 mW at no-load, reducing self-discharge in battery management systems.

Devices from the InnoSwitch family are now available with Silicon, Gallium Nitride (GaN) and high-voltage SiC transistors. “InnoSwitch devices allow the electronics to safely sip from the firehose of energy available on the main bus, using minimal board area. Most exciting is the opportunity to simplify the emergency power supply for the main traction inverter, which may be called upon at a moment’s notice to operate from any voltage between 30 volts and 1000 volts. Our SiC-based InnoSwitch3-AQ handle this vast range with incredible ease,” Vaughan states.

Offered in a compact InSOP™-24D package, the new ICs use a FluxLink™ magneto-inductive feedback link, providing reinforced isolation up to 4.5 kV hi-pot production testing. FluxLink enables direct sensing of the output voltage, providing benefits such as accurate regulation (3 %) and fast transient response. The circuit will start from 30 V without external circuitry – critical for functional safety. Additional protection features include input under-voltage, output over-voltage and over-current limiting. Switching frequency is with 60 kHz relatively low due to the transformer´s characteristics.

The InnoSwitch3-AQ 1700-V parts are also suitable for industrial markets, where the integrated solution can replace discrete controller-plus-MOSFET designs in applications such as renewables, industrial motor drives, battery storage and metering.

Devices are priced at $5.64 for part number INN3947CQ-TL and $9.02 for part number INN3949CQ-TL in volume product quantities. A reference design, DER-913Q, and hardware kit RDK-919Q, are available. AS

www.power.com