A 16-24V to 1-1.8V 1.187W/mm³-Power-Density Hybrid DC-DC Converter Featuring Inductor Current in $\Sigma$-Fibonacci Region for Unmanned Aerial Vehicle Applications

This paper presents a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$16-24 ~\mathrm{V}$</tex>-input <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1-1.8 ~\mathrm{V}$</tex>-output <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3 / 2$</tex>-phase hybrid DC-DC converter for powering point-of-load systems in unmanned aerial vehicles. The converter minimizes inductor DC resistance and AC resistance losses by reducing inductor current into the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Sigma$</tex>-Fibonacci region, enabling the use of a compact inductor. This region corresponds to the minimum achievable inductor current with flying capacitors fully utilized. Fabricated in a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.18 \mu ~\mathrm{m}$</tex> BCD process, the converter achieves a 93.9 % peak efficiency and a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.187 ~\mathrm{W} / \text{mm}^{3}$</tex> power density.