Thesis deals with efficiency of a single-stage buck converter when a large ratio between the input and the output voltage occurs. The emphasis is on so-called converter with extended duty cycle, whose operation is achieved without the use of magnetic components – excluding the output inductors - and consequently without unwanted over voltages. For the proposed topology of converter with two transverse capacitors a detailed analysis of operating conditions is given, highlighting the favourable voltage distribution on power switches and reduction of the switching losses and inherent current distribution among interleaved output branches.
Laboratory model with output parameters 3 V/30 A provides basic guidelines for dimensioning of components. Despite the increased number of power switches experimental results confirm the estimated increase of converter’s efficiency. A uniform distribution of currents between two output inductors is also achieved, thus simplifying the implementation of the control circuit, too.