Flyback transformers series extended for onboard EV/PHV AC/DC battery chargers

Flyback transformers are very popular for cost-effective, high-efficiency isolated power converters from one to tens of Watts power size. The new PREMO FLYT-004 and FLYT-005 transformers are ideal for onboard EV/PHV AC/DC battery chargers and provide quasi-resonant Flyback mode with a switching frequency of 50kHz-300kHz and a maximum duty cycle of 85%. They offer high circuit isolation, multiple outputs and the potential of positive or negative output voltages.

The isolation between primary and secondary windings is a crucial feature. The transformer has been developed to withstand high voltage spikes during switching. The transformers are also intended to offer adequate isolation to satisfy safety requirements (up to 3kV between windings for reinforced isolation level).

The FLYT-004 offers an inductance of 17.5µH and a power of 10W. The FLYT-005 provides an inductance of 15µH and a similar power. Both designs suit SMT soldering on PCBs. The specific SMD customised bobbin design ensures mechanical performance and reliability, taking into final size with its nominal power.

OBCs are commonly integrated into the vehicle's powertrain and need transformers to convert the AC power from external charging stations or home charging units into the DC power required to charge the vehicle's battery. Flyback transformers are required for the power supply control unit to deliver several different low voltages.

PCIM Europe 2023, Stand Hall 6, Stand 232, 9-11 May.