In this paper, a fully integrated active rectifier with triple feedback loops is proposed to enhance power conversion efficiency (PCE) over a wide loading range by calibrating both the gate transition timing and power switch size. The on- and off-transitions of the power switches are calibrated using a hybrid delay-based gate control circuit (HDGCC) with hybrid feedback loops. Conventional active rectifiers that only focused on calibrating the gate transition timing of a NMOS power switch with a fixed power switch size exhibit a low PCE when the loading condition deviates from the predetermined range. Thus, an automatic size selector based on a third feedback loop is proposed, which changes the power switch size based on the loading condition and ensures a stable operation of the hybrid loops by maintaining the voltage drop across the NMOS switches. An active rectifier was fabricated using the standard 0.18 μm CMOS process. The effectiveness and robustness of the two-dimensional calibration were verified through measurements under an AC input voltage ranging from 2.5 to 5.0 V and an output power ranging from 1.25 to 125 mW. The peak voltage conversion ratio and peak PCE were 97.6% and 95.0%, respectively, at RL = 500 Ω.

中文翻译：

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用于无线供电可植入生物医学设备的 6.78 MHz、95.0% 峰值效率单片二维校准有源整流器


在本文中，提出了一种具有三重反馈环路的完全集成有源整流器，通过校准栅极转换时序和功率开关尺寸来提高宽负载范围内的功率转换效率（PCE）。电源开关的通断转换使用具有混合反馈环路的混合延迟栅极控制电路 (HDGCC) 进行校准。传统的有源整流器仅专注于校准具有固定功率开关尺寸的 NMOS 功率开关的栅极转换时序，当负载条件偏离预定范围时，其 PCE 较低。因此，提出了一种基于第三反馈环路的自动尺寸选择器，其根据负载条件改变功率开关尺寸，并通过维持NMOS开关两端的压降来确保混合环路的稳定运行。有源整流器采用标准 0.18 μm CMOS 工艺制造。通过在交流输入电压范围为2.5至5.0 V、输出功率范围为1.25至125 mW的情况下进行测量，验证了二维校准的有效性和鲁棒性。当 RL = 500 Ω 时，峰值电压转换比和峰值 PCE 分别为 97.6% 和 95.0%。