A 6.78-MHz fully integrated single-stage wireless charger with constant-current constant-voltage (CC-CV) charging technique for resonant wireless power transfer applications is presented. Based on the principle of three-mode reconfigurable resonant regulating ( $R^{3}$ ) rectifier, the proposed charger achieves high efficiency and low cost by realizing power rectification, voltage regulation, and CC-CV charging in a single power stage. The power stage of the proposed charger consists of only four nMOS power transistors. A bootstrapping technique using a single-input-dual-output voltage doubler with adaptive phase control is also proposed to integrate bootstrap capacitors on-chip. The CC loop and the CV loop share the same pulsewidth modulation (PWM) controller with smooth transition from the CC mode to the CV mode. An on-chip current sensing and estimation circuit is specially designed for the CC loop. Fabricated in a standard 0.35- $\mu \text{m}$ CMOS process with a die area of 8 mm², the charger delivered a maximum charging current of 1.5 A, and the measured peak efficiency reached 92.3% and 91.4% when the charging currents were 1 A and 1.5 A, respectively.

中文翻译：

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采用恒流恒压充电技术的 6.78MHz 单级无线充电器

介绍了一种 6.78MHz 全集成单级无线充电器，采用恒流恒压 (CC-CV) 充电技术，适用于谐振无线电力传输应用。基于三模可重构谐振调节原理（ $R^{3}$ ) 整流器，所提出的充电器通过在单个功率级中实现功率整流、电压调节和 CC-CV 充电来实现高效率和低成本。建议充电器的功率级仅包含四个 nMOS 功率晶体管。还提出了使用具有自适应相位控制的单输入双输出倍压器的自举技术，以在片上集成自举电容器。CC 环路和 CV 环路共享同一个脉宽调制 (PWM) 控制器，可以从 CC 模式平滑过渡到 CV 模式。片上电流检测和估计电路是专门为 CC 回路设计的。以标准 0.35- $\mu \text{m}$ CMOS工艺，芯片面积为8 mm ²，充电器提供的最大充电电流为1.5 A，当充电电流为1 A和1.5 A时，测得的峰值效率分别达到92.3%和91.4%。