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  1. null (Ed.)
    This paper presents a voltage multiplier topology that is suitable for a low-ripple high-voltage dc generation. The topology has a number of voltage multipliers connected in series and driven at different phases. Compared to a single-phase multiplier, an n-phase voltage multiplier has an output ripple that is smaller by n times. Since the ripple frequency is simultaneously increased by n times, a simple RC lowpass filter further reduces the ripple amplitude by n times, resulting in ripple reduction of n^2 times. We demonstrate the ripple reduction of the proposed topology using a 6 V-to-800 V power supply with a 16-stage four-phase bipolar voltage multiplier. The output ripple frequency is eight times the converter's switching frequency and the ripple amplitude is significantly smaller than the conventional single-phase voltage multiplier. 
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  2. We develop a small and lightweight high-voltage high-gain power converter for applications where weight and size are premium. By driving a Dickson and Cockcroft-Walton voltage multiplier with a megahertz-frequency class-E inverter, we implement two converters, one that achieves 40 V-to-2 kV conversion with 16 cm3 box volume and the other that achieves 3.7 V-to-2.9 kV conversion with 0.2 cm3 box volume and 0.49 g weight. Presented converters achieve comparable or better power density and specific power to those of commercial high-voltage power supplies. 
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  3. This paper presents a voltage multiplier topology that is a hybrid between a Cockcroft-Walton multiplier and a Dickson charge pump. The Cockcroft-Walton structure exhibits significant output voltage drop under load as the number of multiplier stage increases. This is because all coupling capacitors are connected in series. Dickson charge pump mitigates this issue by connecting all capacitors in parallel. But this solution comes at the expense of large capacitor voltage stress at the last multiplier stage. The proposed hybrid structure arranges some capacitors in parallel and others in series, thereby achieving low output voltage drop and low capacitor voltage stress at the same time. We develop a model that predicts hybrid multiplier's performance and validate it experimentally. We also demonstrate a 60 V-to-2.25 kV dc-dc converter based on a 16-stage hybrid voltage multiplier which achieves a voltage gain of 12.8 while keeping the highest capacitor voltage stress to 660 V. 
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  4. This paper presents the design of a compact 45 V-to-54 kV dc-dc converter for high-energy beam applications with the focus on X-ray generation. We describe key design choices for a high power density including a modular structure, high-frequency switching, planar transformers and Dickson topology. High-voltage insulation and thermal management are also described in detail. The experimental data with a 5 kV single module and a 10-module 54 kV converter indicate that the proposed structure can generate high dc voltage while achieving a several times higher power density compared to commercial high-voltage power supplies. 
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