A 25 MHz Fast Transient Adaptive-On/Off-Time Controlled Three-Level Buck Converter
A 25 MHz Fast Transient Adaptive-On/Off-Time Controlled Three-Level Buck Converter
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25 MHz 快速瞬态自适应开/关时间控制的三电平降压转换器
DOI：
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
P. Mok
中科院分区：
文献类型：
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作者：
Sijie Pan;P. Mok
本文提出了一种25 MHz自适应开关时间控制的三电平降压变换器，具有快速的参考跟踪速度和高的轻载效率。飞跨电容电压的自平衡方案进行了修改和扩展的宽转换比范围从0.17到0.833。为了减小自平衡方案应用于带片内飞跨电容的高频三电平降压变换器时的误差，引入了飞跨电容电压实时校准环路，有效地将平衡误差从340 mV减小到20 mV。提出了一种三电平降压变换器的输出电压转折点预测方法，以实现接近最优的参考跟踪，具有快速的跟踪速度和可忽略的输出电压下冲或过冲。在电感为47 nH、输出电容为47 nF的情况下，1 V步进的上跟踪和下跟踪分别需要81 ns和72 ns。该三电平变换器通过基于反馈回路的方法实现了在轻载时具有自适应开关频率的精确不连续导通模式（DCM）操作。负载为10 mA时，效率提高约28.2%。三电平降压变换器的峰值效率为92.8%，在大多数工作区域效率都在85%以上。
This work presents a 25 MHz adaptive on/off-time-controlled three-level buck converter with a fast reference tracking speed and high light load efficiency. The self-balancing scheme of the flying capacitor voltage is revised and extended for a broad conversion ratio range from 0.17 to 0.833. To reduce the error of the self-balancing scheme when applied to a high frequency three-level buck converter with an on-chip flying capacitor, a real-time calibration loop on the flying capacitor voltage is introduced, effectively reducing the balancing error from 340 mV to 20 mV. A turning-point output voltage prediction for the three-level buck converter is presented to achieve near-optimal reference tracking with a fast tracking speed and negligible output voltage undershoot or overshoot. The up- and down-tracking takes 81 ns and 72 ns, respectively, for a 1-V step with an inductor of 47 nH and an output capacitor of 47 nF. The three-level converter achieves a precise discontinuous conduction mode (DCM) operation with an adaptive switching frequency at light load by means of a feedback loop-based method. An approximately 28.2% increment in efficiency is achieved with a load of 10 mA. The three-level buck converter has a peak efficiency of 92.8% and an over 85% efficiency in most of the operation regions.