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A new light emitting diode (LED) driver circuit is presented in this paper based on the buck converter with coupled inductors for automotive applications. Soft-switching condition is provided for the switch via a passive resonant circuit incorporating the leakage inductance of the coupled inductors. Also, the leakage inductance energy is recycled to the output. The proposed converter has a very simple structure as well as high efficiency, which makes it a good candidate for battery-operated applications. The proposed converter only applies one magnetic element and the leakage and magnetizing inductances are used as resonant elements. Also, during the resonance, a resonance capacitor is approximately charged to the input voltage, and therefore, the capacitor voltage stress and semiconductor devices voltage stress are low. These are the main advantages of the proposed converter over other similar converters. The theoretical analysis is provided and the operating principles and design considerations are explained. An 8 W laboratory prototype is implemented in order to prove the validity of the theoretical analysis. [ABSTRACT FROM AUTHOR]

A simple buck–boost LED driver suitable for battery operated applications with limited input voltage level is presented in this paper. Soft switching performance is provided for the main switch via a resonant circuit to improve the converter efficiency. The incorporated auxiliary switch also performs under zero voltage switching condition. Both power switches can be driven with a simple gate drive circuit, so, the additional switch does not add any driving complexity. In addition, only one magnetic element is utilized in the proposed LED driver which contributes to circuit simplicity and lower weight and size. Also, all diodes turn off at zero current switching which eliminates the reverse recovery losses and improves efficiency. A laboratory prototype converting 12 V input voltage to 32 V output operating at 26 W output power is implemented and tested to verify the effectiveness of the proposed LED driver. [ABSTRACT FROM AUTHOR]