Design of high-power-density DC-DC converter IC covering wide conversion ratio

Abstract

As the demand for fast charging of batteries increases, the load current of battery charging modules is also on the rise. In order to achieve high efficiency and power density even under heavy load condition, research on the inductor-capacitor hybrid topology, utilizing parallelized inductor current and capacitor current, is actively underway. However, prior hybrid topologies have a drawback in that the current distribution ratio between inductor and capacitor is highly sensitive to the voltage conversion ratio (VCR), making it challenge to achieve high efficiency across a wide VCR range. In this paper, a new hybrid topology is proposed that achieves a consistent current distribution ratio and high efficiency over a wide VCR range. The proposed topology has achieved a maximum efficiency of $96.4%$ under heavy load condition of $2A$ and a high current density of $132mA/mm^3$. Furthermore, it achieved over $90%$ efficiency in the VCR range of $0.25$ to $0.9$.