A series of new reference designs featuring a 1700 V-rated silicon carbide (SiC) integrated flyback switcher IC for use in electric vehicles operating at 800 V has been developed. These designs address multiple auxiliary power requirements, including DC-DC bus conversion, emergency power for inverters, battery management systems, and other auxiliary loads. Output power levels range from 16 W to 120 W, and traditional wound and low-profile planar transformers are utilized.
The designs use a wide-creepage InSOP™-28G package that offers 1000 VDC primary side support and extended creepage and clearance to meet safety and reliability standards in pollution degree 2 environments. The package includes a 5.1 mm creepage distance from drain to source pins, which supports functional isolation and may remove the need for conformal coating in some applications, simplifying the manufacturing process.
Five specific design implementations are included. There are reference design kits (RDKs): a 35 W solution for inverter gate-drive and emergency power with a 40–1000 VDC input and 24 V output; an 18 W version using a planar transformer for similar applications; and a 120 W supply capable of reducing or replacing 12 V batteries. Two design example reports (DERs) are available: a 20 W four-output power supply including emergency and gate-drive outputs, and a 16 W four-output unit with 14 V and split-rail outputs.
The InnoSwitch3-AQ ICs integrate a 1700 V SiC power switch and a CV/CC flyback controller capable of operating in both discontinuous and continuous conduction modes. These ICs incorporate synchronous rectification and valley switching, achieving efficiencies greater than 91%. The devices operate with minimal external components, which can reduce bill-of-materials complexity and board space. The ICs initiate startup at drain voltages as low as 30 V without external biasing, a feature relevant to functional safety. Additional protection features include under-voltage lockout, output over-voltage, and current limit functions. Standby power consumption is rated at under 15 mW.
The ICs and associated reference kits are currently available. Unit pricing starts at $6 in quantities of 10,000, and reference design kits are priced between $50 and $100.
