Power Integrations announced the production release of the InnoSwitch3-AQ, an AEC-Q100-qualified flyback switcher with integrated 750 V MOSFET and secondary-side sensing. The newly qualified device family targets automotive EV applications, such as traction inverter, OBC (on-board charger), EMS (energy management DC/DC bus converters), and BMS (battery management systems).
The InnoSwitch3-AQ uses Power Integrations’ high-speed FluxLink coupling to achieve ±3% accuracy for combined line and load regulation while eliminating both dedicated isolated transformer sense-windings and optocouplers. FluxLink technology maintains output voltage regulation even under the transient stress test, which is particularly challenging for PSR-based implementations. The integrated 750 V MOSFET meets stringent automotive de-rating requirements, and an on-chip synchronous rectifier controller delivers above 90% efficiency at the nominal 400 VDC input voltage. Optimized InnoSwitch3-AQ designs achieve less than 10 mW no-load energy usage across the input voltage range. The InnoSwitch3-AQ family ICs are packaged in a surface-mount InSOP with 11 mm primary to secondary creepage, which exceeds the stringent requirements for high altitude (> 5000 m) isolation.
“In order to avoid using optocouplers, EV makers are using primary-side regulation (PSR) which is not as accurate – especially across line and load,” says Andy Smith Director of Training, Power Integrations. “The loss of output control necessitates the use of secondary-side post regulating DC-DC converters to ensure a constant voltage output. The DC-DC stage is expensive, adds parts (reliability, etc.) and reduces conversion efficiency. We don’t have those issues with Fluxlink and InnoSwitch-3 which ensures very accurate output regulation.”
Smith continues: “Automotive electronics is using a voltage rating up from 400V to 800V. This has been done a long time in high-performance cars but is now happening in other cars. However, moving over to higher voltage with an 800V DC rail becomes more of a challenge for our switching transistor. So we have incorporated our StackFET technology. With this technology, you basically put another switch in series with the main power switch for the device, and that allows you to split the voltage properly across the two devices. So, if we have a higher voltage bus we simply insert another transistor, as well as our switching transistor, and the problem goes away. Ironically, introducing StackFET actually helps thermal performance as well because not only do you have all the high voltage ratings in automotive, temperature requirements are critical, as well, and automotive environments can be up to 100 degrees C ambient in some applications. So InnowSwitch3-AQ with StackFET allows you to split any switch heating effect between two switches and not just one, thereby dispersing the heat.”
The DER-840Q reference design incorporating the newly released IC demonstrates start-up, shutdown and efficient operation from 30 VDC to 550 VDC input, as well as fast transient response and a variety of safety and protection features. InnoSwitch3-AQ ICs are available in the InSOP-24D package. Devices are available now with prices starting at $2.75 in 10,000-piece quantities.
