The resonant switch mode inductor-less electronic transformer for halogen lamp

The resonant inductor-less electronic transformer (ET) for low-voltage halogen lamps based on class-D zero voltage switching (ZVS) inverter is presented and experimented. The leakage inductance of the high frequency transformer is used as the resonant inductor of the resonant circuit. The ZVS condition can be maintained from full-loaded to no-loaded or when lamp is removed or filament is opened. The experimental results show the operation of the 50 W-12 V output prototype at 53 kHz switching frequency. The measured efficiency is greater than 95 percent, nearly unity power factor. Moreover, the dimmable feature and soft-starting can be achieved by simple control.