This letter proposes a loop-free autocalibration technique for self-balancing of flying capacitors in a three-level dc–dc buck converter. The proposed converter utilizes a dual-path power stage with balancing switches that adaptively short flying capacitors at de-energizing phases. Thus, the dual-path three-level converter ensures that flying capacitor voltages are self-balanced at half the input voltage without using additional feedback calibration loops, leading to robust operation and competitive efficiencies. The prototype was fabricated in the 0.13-μm CMOS BCD process and adopted two flying capacitors of 4.7 μF each and an inductor of 10 μH with a dc resistance of 128 mΩ. When an 8-V input was converted to a 3-V output voltage with a load current of 400 mA, the measured efficiency was 88.6% at 800 kHz switching while flying capacitors are automatically balanced.

中文翻译：

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具有无环路自动校准功能的双路三电平降压转换器，用于飞跨电容器自平衡

这封信提出了一种用于三电平 DC-DC 降压转换器中飞跨电容器自平衡的无环路自动校准技术。所提出的转换器使用带有平衡开关的双路径功率级，可在断电阶段自适应地缩短飞跨电容器。因此，双路径三电平转换器可确保快速电容器电压在输入电压的一半处自平衡，而无需使用额外的反馈校准回路，从而实现稳健的运行和具有竞争力的效率。该原型采用 0.13-μm CMOS BCD 工艺制造，采用两个 4.7 μF 的飞跨电容器和一个 10 μH 的电感器，直流电阻为 128 mΩ。在负载电流为 400 mA 的情况下，将 8V 输入转换为 3V 输出电压时，测得的效率为 88。