E-Mobility Engineering 019 | In conversation: Stephen Lambert l WAE EVR l Battery case materials focus l Quality control insight l Clipper Automotive Clipper Cab digest l Optimising battery chemistries insight l Powertrain testing focus

6 May/June 2023 | E-Mobility Engineering The Grid GaN switch for 400Vpowertrains P ower Integrations has developed a 900V flyback switching chip with a galliumnitride transistor for more efficient 400V powertrain designs (writes Nick Flaherty). The InnoSwitch3-AQ uses the company’s proprietary PowiGaN transistor to provide up to 100Wwith an efficiency of up to 93%, eliminating the need for heat sinks and allowing a smaller system design. The switcher’s design allows 400 V systems to provide performance and protection features similar to those of the 1700 V SiC devices currently used in 800 V systems. “The dominant bus voltage for EVs is 400 V,” said Peter Vaughan, automotive business development director at Power Integrations. “EV manufacturers are optimising their new generation of 400 V systems and re-engineering various power stages in the vehicle, such as the onboard charger. The 900 V PowiGaN switch accommodates the highly inductive noise spikes often present in automotive environments.” To achieve the efficiency, the InnoSwitch3-AQ uses synchronous rectification, a valley switching discontinuous conduction mode and a continuous conduction mode flyback controller. PI’s FluxLink isolation technology enables the chip package to bridge the isolation barrier between the 12 V battery and the 400 V powertrain, eliminating the need for optocouplers. POWERTRAINS The InnoSwitch3-AQ’s design allows 400 V systems to provide performance and protection features similar to those of a 1700 V SiC device