Design of Scalable Hybrid Boost Converter With Optimal Number of Stages for High Conversion Ratio and High Power Efficiency

This paper presents a scalable hybrid boost converter (SHBC) with adjusted number of stages (N) to acquire high conversion ratio (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CR</i>) and high power efficiency. Firstly, unlike most converters where <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CR</i> is related only to duty cycle (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i>), the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CR</i> of SHBC is related to both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> and N. This allows the converter to provide a high <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CR</i> while keeping <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> at a reasonable value for easy loop control. Secondly, N flying capacitors in series with the inductor can divide output voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm {OUT}}$</tex-math> </inline-formula>) to use low voltage devices with small figure of metric (FOM) for high power efficiency. Moreover, N flying capacitors in parallel with the inductor can shunt the inductor current to reduce the inductor DCR loss, which also helps improve power efficiency. Thirdly, when many N values meet the requirements of a specific application scenario, an optimal number of stages (N<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OPT</sub>) is proposed to minimize the total loss and optimize the power efficiency further. The prototype design of SHBC with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{N}_{\mathrm {OPT}} =2$</tex-math> </inline-formula> has been discussed and fabricated by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18~\mu $</tex-math> </inline-formula>m BCD process. The measurement results demonstrate its operation is normal in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CR</i> range from 4 to 8. Besides, a 93.34% peak efficiency is also achieved with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I_{\mathrm {OUT}} =0.125$</tex-math> </inline-formula> A and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CR</i> = 4.