An Up-to-70-V Output Hybrid Boost Converter with Halved Voltage Stress Achieving 7-W Output Power and 73.8% Peak Efficiency at CR of 14

High voltage DC-DC boost converters are essential for a variety of applications, including LED backlighting [1], piezoelectric actuators [2], the bias of optoelectronic devices in LiDAR systems [3], and so on. Given that the input voltage is relatively low when powered by a lithium-ion (Li-ion) battery, achieving a high conversion ratio (CR) is crucial. A conventional boost topology is illustrated in Fig. 1 (top). To realize high CR and output voltage, several challenges arise: 1) The limited CR of conventional boost brings a large duty ratio <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$D$</tex>, which not only restricts the switching frequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{F}_{\text{SW}})$</tex> due to the minimum on-time of power switches, but also leads to a significant inductor current ripple. 2) The power switches and inductor suffer from high voltage stress due to the elevated output voltage, necessitating the use of high-voltage LDMOS and inductors. This, in turn, results in larger on-resistance, ultimately reducing power conversion efficiency. 3) As the CR increases, the ratio between the inductor current <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$l_{\mathrm{L}}$</tex> and the output current <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$l_{\text{OUT}}$</tex> rises, resulting in a higher average inductor current in high CR converters than those with lower CR.