A major challenge in the implementation of flying capacitor multilevel (FCML) converters and hybrid switched-capacitor (SC) converters is providing gate drive power to the large number of floating switches. A common solution uses isolated dc/dc converters, which are bulky, expensive, and energy inefficient. To design more compact and efficient gate drive power supply circuits, five methods are presented and compared in this article: bootstrap at deadtime, cascaded bootstrap with low-dropout (LDO) regulator, double charge pump, gate-driven charge pump, and synchronous bootstrap. By leveraging the inherent properties of multilevel converters, these methods can overcome the limitation of conventional bootstrap method (diode forward voltage drop) and make it possible to transfer ground-referenced power to all of the floating switches for any FCML or hybrid SC converters. Compared with the typical isolated dc/dc solution, these methods have simple structure and operating principle and can be implemented with a small number of diodes, capacitors, and LDOs. Experimental results show that an example power supply circuit can cut the size of the power stage of a state of the art seven-level FCML converter by half at 1/6 of the cost.

中文翻译：

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改进的自举方法，用于为飞跨电容多电平转换器和混合开关电容器转换器的浮动栅极驱动器供电


飞跨电容多电平 （FCML） 转换器和混合开关电容器 （SC） 转换器实施的一个主要挑战是为大量浮动开关提供栅极驱动电源。一种常见的解决方案使用隔离式 DC/DC 转换器，这种转换器体积庞大、价格昂贵且能效低下。为了设计更紧凑、更高效的栅极驱动电源电路，本文提出并比较了五种方法：死区时间自举、带低压差 （LDO） 稳压器的级联自举、双电荷泵、栅极驱动电荷泵和同步自举。通过利用多电平转换器的固有特性，这些方法可以克服传统自举方法（二极管正向电压降）的限制，并可以将以地为参考的功率传输到任何 FCML 或混合 SC 转换器的所有浮动开关。与典型的隔离式 DC/DC 解决方案相比，这些方法具有简单的结构和工作原理，并且只需少量的二极管、电容器和 LDO 即可实现。实验结果表明，一个示例电源电路可以以 1/6 的成本将最先进的 7 电平 FCML 转换器的功率级尺寸减小一半。