A Hybrid Boost Converter with Regulated Flying Capacitor Voltage and Reduced Inductor Current for LED Lighting

Abstract

This paper proposes a hybrid boost converter for $\gt100V$ LED lighting applications. The proposed boost converter uses one flying capacitor to reduce the switch voltage stress, average inductor current, and inductor current ripple, and also to prolong the duty cycle (D) for the same voltage conversion ratio (M). Therefore, the proposed topology has reduced switching, conduction, and core losses, exhibiting also an enhanced step-up capability. Hence, the proposed boost converter considerably improves the power conversion efficiency (PCE), with M=(2–D)/(1–D). Besides, the proposed boost converter automatically sets the voltage on the flying capacitor to V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT</inf> – $\mathrm{V}_{IN}$. Here, we simulate both the conventional and the proposed boost converters in Cadence Spectre with commercial device models. The proposed boost converter improves the peak PCE from 96.8% to 97.4%, with ${V}_{IN}=24V, V_{OUT} =103.5V$, and I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT</inf> =1 A. That is equivalent to 18.75% total loss reduction.